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20c8ccb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
71e3aac0 AA |
2 | /* |
3 | * Copyright (C) 2009 Red Hat, Inc. | |
71e3aac0 AA |
4 | */ |
5 | ||
ae3a8c1c AM |
6 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
7 | ||
71e3aac0 AA |
8 | #include <linux/mm.h> |
9 | #include <linux/sched.h> | |
fa6c0231 | 10 | #include <linux/sched/mm.h> |
f7ccbae4 | 11 | #include <linux/sched/coredump.h> |
6a3827d7 | 12 | #include <linux/sched/numa_balancing.h> |
71e3aac0 AA |
13 | #include <linux/highmem.h> |
14 | #include <linux/hugetlb.h> | |
15 | #include <linux/mmu_notifier.h> | |
16 | #include <linux/rmap.h> | |
17 | #include <linux/swap.h> | |
97ae1749 | 18 | #include <linux/shrinker.h> |
ba76149f | 19 | #include <linux/mm_inline.h> |
e9b61f19 | 20 | #include <linux/swapops.h> |
fb5c2029 | 21 | #include <linux/backing-dev.h> |
4897c765 | 22 | #include <linux/dax.h> |
ba76149f | 23 | #include <linux/khugepaged.h> |
878aee7d | 24 | #include <linux/freezer.h> |
f25748e3 | 25 | #include <linux/pfn_t.h> |
a664b2d8 | 26 | #include <linux/mman.h> |
3565fce3 | 27 | #include <linux/memremap.h> |
325adeb5 | 28 | #include <linux/pagemap.h> |
49071d43 | 29 | #include <linux/debugfs.h> |
4daae3b4 | 30 | #include <linux/migrate.h> |
43b5fbbd | 31 | #include <linux/hashtable.h> |
6b251fc9 | 32 | #include <linux/userfaultfd_k.h> |
33c3fc71 | 33 | #include <linux/page_idle.h> |
baa355fd | 34 | #include <linux/shmem_fs.h> |
6b31d595 | 35 | #include <linux/oom.h> |
98fa15f3 | 36 | #include <linux/numa.h> |
f7da677b | 37 | #include <linux/page_owner.h> |
a1a3a2fc | 38 | #include <linux/sched/sysctl.h> |
467b171a | 39 | #include <linux/memory-tiers.h> |
97ae1749 | 40 | |
71e3aac0 AA |
41 | #include <asm/tlb.h> |
42 | #include <asm/pgalloc.h> | |
43 | #include "internal.h" | |
014bb1de | 44 | #include "swap.h" |
71e3aac0 | 45 | |
283fd6fe AK |
46 | #define CREATE_TRACE_POINTS |
47 | #include <trace/events/thp.h> | |
48 | ||
ba76149f | 49 | /* |
b14d595a MD |
50 | * By default, transparent hugepage support is disabled in order to avoid |
51 | * risking an increased memory footprint for applications that are not | |
52 | * guaranteed to benefit from it. When transparent hugepage support is | |
53 | * enabled, it is for all mappings, and khugepaged scans all mappings. | |
8bfa3f9a JW |
54 | * Defrag is invoked by khugepaged hugepage allocations and by page faults |
55 | * for all hugepage allocations. | |
ba76149f | 56 | */ |
71e3aac0 | 57 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 58 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 59 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
60 | #endif |
61 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
62 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
63 | #endif | |
444eb2a4 | 64 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
65 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
66 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 67 | |
54d91729 QZ |
68 | static struct shrinker *deferred_split_shrinker; |
69 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
70 | struct shrink_control *sc); | |
71 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
72 | struct shrink_control *sc); | |
f000565a | 73 | |
97ae1749 | 74 | static atomic_t huge_zero_refcount; |
56873f43 | 75 | struct page *huge_zero_page __read_mostly; |
3b77e8c8 | 76 | unsigned long huge_zero_pfn __read_mostly = ~0UL; |
4a6c1297 | 77 | |
a7f4e6e4 ZK |
78 | bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags, |
79 | bool smaps, bool in_pf, bool enforce_sysfs) | |
7635d9cb | 80 | { |
9fec5168 YS |
81 | if (!vma->vm_mm) /* vdso */ |
82 | return false; | |
83 | ||
7da4e2cb YS |
84 | /* |
85 | * Explicitly disabled through madvise or prctl, or some | |
86 | * architectures may disable THP for some mappings, for | |
87 | * example, s390 kvm. | |
88 | * */ | |
89 | if ((vm_flags & VM_NOHUGEPAGE) || | |
90 | test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) | |
9fec5168 | 91 | return false; |
7da4e2cb YS |
92 | /* |
93 | * If the hardware/firmware marked hugepage support disabled. | |
94 | */ | |
3c556d24 | 95 | if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED)) |
c0630669 | 96 | return false; |
c0630669 | 97 | |
7da4e2cb | 98 | /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ |
9fec5168 | 99 | if (vma_is_dax(vma)) |
7da4e2cb YS |
100 | return in_pf; |
101 | ||
102 | /* | |
7a81751f | 103 | * khugepaged special VMA and hugetlb VMA. |
7da4e2cb YS |
104 | * Must be checked after dax since some dax mappings may have |
105 | * VM_MIXEDMAP set. | |
106 | */ | |
7a81751f | 107 | if (!in_pf && !smaps && (vm_flags & VM_NO_KHUGEPAGED)) |
c0630669 | 108 | return false; |
9fec5168 | 109 | |
7da4e2cb YS |
110 | /* |
111 | * Check alignment for file vma and size for both file and anon vma. | |
112 | * | |
113 | * Skip the check for page fault. Huge fault does the check in fault | |
114 | * handlers. And this check is not suitable for huge PUD fault. | |
115 | */ | |
116 | if (!in_pf && | |
117 | !transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE))) | |
9fec5168 YS |
118 | return false; |
119 | ||
7da4e2cb YS |
120 | /* |
121 | * Enabled via shmem mount options or sysfs settings. | |
122 | * Must be done before hugepage flags check since shmem has its | |
123 | * own flags. | |
124 | */ | |
125 | if (!in_pf && shmem_file(vma->vm_file)) | |
2cf13384 DS |
126 | return shmem_is_huge(file_inode(vma->vm_file), vma->vm_pgoff, |
127 | !enforce_sysfs, vma->vm_mm, vm_flags); | |
9fec5168 | 128 | |
a7f4e6e4 ZK |
129 | /* Enforce sysfs THP requirements as necessary */ |
130 | if (enforce_sysfs && | |
131 | (!hugepage_flags_enabled() || (!(vm_flags & VM_HUGEPAGE) && | |
132 | !hugepage_flags_always()))) | |
9fec5168 YS |
133 | return false; |
134 | ||
7a81751f ZK |
135 | if (!vma_is_anonymous(vma)) { |
136 | /* | |
137 | * Trust that ->huge_fault() handlers know what they are doing | |
138 | * in fault path. | |
139 | */ | |
140 | if (((in_pf || smaps)) && vma->vm_ops->huge_fault) | |
141 | return true; | |
142 | /* Only regular file is valid in collapse path */ | |
143 | if (((!in_pf || smaps)) && file_thp_enabled(vma)) | |
144 | return true; | |
9fec5168 | 145 | return false; |
7a81751f | 146 | } |
9fec5168 YS |
147 | |
148 | if (vma_is_temporary_stack(vma)) | |
149 | return false; | |
150 | ||
151 | /* | |
152 | * THPeligible bit of smaps should show 1 for proper VMAs even | |
153 | * though anon_vma is not initialized yet. | |
7da4e2cb YS |
154 | * |
155 | * Allow page fault since anon_vma may be not initialized until | |
156 | * the first page fault. | |
9fec5168 YS |
157 | */ |
158 | if (!vma->anon_vma) | |
7da4e2cb | 159 | return (smaps || in_pf); |
9fec5168 YS |
160 | |
161 | return true; | |
7635d9cb MH |
162 | } |
163 | ||
aaa9705b | 164 | static bool get_huge_zero_page(void) |
97ae1749 KS |
165 | { |
166 | struct page *zero_page; | |
167 | retry: | |
168 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
aaa9705b | 169 | return true; |
97ae1749 KS |
170 | |
171 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 172 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
173 | if (!zero_page) { |
174 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
aaa9705b | 175 | return false; |
d8a8e1f0 | 176 | } |
97ae1749 | 177 | preempt_disable(); |
5918d10a | 178 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 179 | preempt_enable(); |
5ddacbe9 | 180 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
181 | goto retry; |
182 | } | |
3b77e8c8 | 183 | WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); |
97ae1749 KS |
184 | |
185 | /* We take additional reference here. It will be put back by shrinker */ | |
186 | atomic_set(&huge_zero_refcount, 2); | |
187 | preempt_enable(); | |
f4981502 | 188 | count_vm_event(THP_ZERO_PAGE_ALLOC); |
aaa9705b | 189 | return true; |
4a6c1297 KS |
190 | } |
191 | ||
6fcb52a5 | 192 | static void put_huge_zero_page(void) |
4a6c1297 | 193 | { |
97ae1749 KS |
194 | /* |
195 | * Counter should never go to zero here. Only shrinker can put | |
196 | * last reference. | |
197 | */ | |
198 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
199 | } |
200 | ||
6fcb52a5 AL |
201 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
202 | { | |
203 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
204 | return READ_ONCE(huge_zero_page); | |
205 | ||
206 | if (!get_huge_zero_page()) | |
207 | return NULL; | |
208 | ||
209 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
210 | put_huge_zero_page(); | |
211 | ||
212 | return READ_ONCE(huge_zero_page); | |
213 | } | |
214 | ||
215 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
216 | { | |
217 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
218 | put_huge_zero_page(); | |
219 | } | |
220 | ||
48896466 GC |
221 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
222 | struct shrink_control *sc) | |
4a6c1297 | 223 | { |
48896466 GC |
224 | /* we can free zero page only if last reference remains */ |
225 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
226 | } | |
97ae1749 | 227 | |
48896466 GC |
228 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
229 | struct shrink_control *sc) | |
230 | { | |
97ae1749 | 231 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
232 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
233 | BUG_ON(zero_page == NULL); | |
3b77e8c8 | 234 | WRITE_ONCE(huge_zero_pfn, ~0UL); |
5ddacbe9 | 235 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 236 | return HPAGE_PMD_NR; |
97ae1749 KS |
237 | } |
238 | ||
239 | return 0; | |
4a6c1297 KS |
240 | } |
241 | ||
54d91729 | 242 | static struct shrinker *huge_zero_page_shrinker; |
97ae1749 | 243 | |
71e3aac0 | 244 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
245 | static ssize_t enabled_show(struct kobject *kobj, |
246 | struct kobj_attribute *attr, char *buf) | |
247 | { | |
bfb0ffeb JP |
248 | const char *output; |
249 | ||
444eb2a4 | 250 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
bfb0ffeb JP |
251 | output = "[always] madvise never"; |
252 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
253 | &transparent_hugepage_flags)) | |
254 | output = "always [madvise] never"; | |
444eb2a4 | 255 | else |
bfb0ffeb JP |
256 | output = "always madvise [never]"; |
257 | ||
258 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 259 | } |
444eb2a4 | 260 | |
71e3aac0 AA |
261 | static ssize_t enabled_store(struct kobject *kobj, |
262 | struct kobj_attribute *attr, | |
263 | const char *buf, size_t count) | |
264 | { | |
21440d7e | 265 | ssize_t ret = count; |
ba76149f | 266 | |
f42f2552 | 267 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
268 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); |
269 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 270 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
271 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
272 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 273 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
274 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
275 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
276 | } else | |
277 | ret = -EINVAL; | |
ba76149f AA |
278 | |
279 | if (ret > 0) { | |
b46e756f | 280 | int err = start_stop_khugepaged(); |
ba76149f AA |
281 | if (err) |
282 | ret = err; | |
283 | } | |
ba76149f | 284 | return ret; |
71e3aac0 | 285 | } |
37139bb0 ML |
286 | |
287 | static struct kobj_attribute enabled_attr = __ATTR_RW(enabled); | |
71e3aac0 | 288 | |
b46e756f | 289 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
bfb0ffeb JP |
290 | struct kobj_attribute *attr, char *buf, |
291 | enum transparent_hugepage_flag flag) | |
71e3aac0 | 292 | { |
bfb0ffeb JP |
293 | return sysfs_emit(buf, "%d\n", |
294 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 295 | } |
e27e6151 | 296 | |
b46e756f | 297 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
298 | struct kobj_attribute *attr, |
299 | const char *buf, size_t count, | |
300 | enum transparent_hugepage_flag flag) | |
301 | { | |
e27e6151 BH |
302 | unsigned long value; |
303 | int ret; | |
304 | ||
305 | ret = kstrtoul(buf, 10, &value); | |
306 | if (ret < 0) | |
307 | return ret; | |
308 | if (value > 1) | |
309 | return -EINVAL; | |
310 | ||
311 | if (value) | |
71e3aac0 | 312 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 313 | else |
71e3aac0 | 314 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
315 | |
316 | return count; | |
317 | } | |
318 | ||
71e3aac0 AA |
319 | static ssize_t defrag_show(struct kobject *kobj, |
320 | struct kobj_attribute *attr, char *buf) | |
321 | { | |
bfb0ffeb JP |
322 | const char *output; |
323 | ||
324 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, | |
325 | &transparent_hugepage_flags)) | |
326 | output = "[always] defer defer+madvise madvise never"; | |
327 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, | |
328 | &transparent_hugepage_flags)) | |
329 | output = "always [defer] defer+madvise madvise never"; | |
330 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, | |
331 | &transparent_hugepage_flags)) | |
332 | output = "always defer [defer+madvise] madvise never"; | |
333 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, | |
334 | &transparent_hugepage_flags)) | |
335 | output = "always defer defer+madvise [madvise] never"; | |
336 | else | |
337 | output = "always defer defer+madvise madvise [never]"; | |
338 | ||
339 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 340 | } |
21440d7e | 341 | |
71e3aac0 AA |
342 | static ssize_t defrag_store(struct kobject *kobj, |
343 | struct kobj_attribute *attr, | |
344 | const char *buf, size_t count) | |
345 | { | |
f42f2552 | 346 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
347 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); |
348 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
349 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
350 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 351 | } else if (sysfs_streq(buf, "defer+madvise")) { |
21440d7e DR |
352 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
353 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
354 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
355 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 356 | } else if (sysfs_streq(buf, "defer")) { |
4fad7fb6 DR |
357 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
358 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
359 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
360 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 361 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
362 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
363 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
364 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
365 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 366 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
367 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
368 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
369 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
370 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
371 | } else | |
372 | return -EINVAL; | |
373 | ||
374 | return count; | |
71e3aac0 | 375 | } |
37139bb0 | 376 | static struct kobj_attribute defrag_attr = __ATTR_RW(defrag); |
71e3aac0 | 377 | |
79da5407 | 378 | static ssize_t use_zero_page_show(struct kobject *kobj, |
ae7a927d | 379 | struct kobj_attribute *attr, char *buf) |
79da5407 | 380 | { |
b46e756f | 381 | return single_hugepage_flag_show(kobj, attr, buf, |
ae7a927d | 382 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
79da5407 KS |
383 | } |
384 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
385 | struct kobj_attribute *attr, const char *buf, size_t count) | |
386 | { | |
b46e756f | 387 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
388 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
389 | } | |
37139bb0 | 390 | static struct kobj_attribute use_zero_page_attr = __ATTR_RW(use_zero_page); |
49920d28 HD |
391 | |
392 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
ae7a927d | 393 | struct kobj_attribute *attr, char *buf) |
49920d28 | 394 | { |
ae7a927d | 395 | return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); |
49920d28 HD |
396 | } |
397 | static struct kobj_attribute hpage_pmd_size_attr = | |
398 | __ATTR_RO(hpage_pmd_size); | |
399 | ||
71e3aac0 AA |
400 | static struct attribute *hugepage_attr[] = { |
401 | &enabled_attr.attr, | |
402 | &defrag_attr.attr, | |
79da5407 | 403 | &use_zero_page_attr.attr, |
49920d28 | 404 | &hpage_pmd_size_attr.attr, |
396bcc52 | 405 | #ifdef CONFIG_SHMEM |
5a6e75f8 | 406 | &shmem_enabled_attr.attr, |
71e3aac0 AA |
407 | #endif |
408 | NULL, | |
409 | }; | |
410 | ||
8aa95a21 | 411 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 412 | .attrs = hugepage_attr, |
ba76149f AA |
413 | }; |
414 | ||
569e5590 | 415 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 416 | { |
71e3aac0 AA |
417 | int err; |
418 | ||
569e5590 SL |
419 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
420 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 421 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 422 | return -ENOMEM; |
ba76149f AA |
423 | } |
424 | ||
569e5590 | 425 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 426 | if (err) { |
ae3a8c1c | 427 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 428 | goto delete_obj; |
ba76149f AA |
429 | } |
430 | ||
569e5590 | 431 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 432 | if (err) { |
ae3a8c1c | 433 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 434 | goto remove_hp_group; |
ba76149f | 435 | } |
569e5590 SL |
436 | |
437 | return 0; | |
438 | ||
439 | remove_hp_group: | |
440 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
441 | delete_obj: | |
442 | kobject_put(*hugepage_kobj); | |
443 | return err; | |
444 | } | |
445 | ||
446 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
447 | { | |
448 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
449 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
450 | kobject_put(hugepage_kobj); | |
451 | } | |
452 | #else | |
453 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
454 | { | |
455 | return 0; | |
456 | } | |
457 | ||
458 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
459 | { | |
460 | } | |
461 | #endif /* CONFIG_SYSFS */ | |
462 | ||
54d91729 QZ |
463 | static int __init thp_shrinker_init(void) |
464 | { | |
465 | huge_zero_page_shrinker = shrinker_alloc(0, "thp-zero"); | |
466 | if (!huge_zero_page_shrinker) | |
467 | return -ENOMEM; | |
468 | ||
469 | deferred_split_shrinker = shrinker_alloc(SHRINKER_NUMA_AWARE | | |
470 | SHRINKER_MEMCG_AWARE | | |
471 | SHRINKER_NONSLAB, | |
472 | "thp-deferred_split"); | |
473 | if (!deferred_split_shrinker) { | |
474 | shrinker_free(huge_zero_page_shrinker); | |
475 | return -ENOMEM; | |
476 | } | |
477 | ||
478 | huge_zero_page_shrinker->count_objects = shrink_huge_zero_page_count; | |
479 | huge_zero_page_shrinker->scan_objects = shrink_huge_zero_page_scan; | |
480 | shrinker_register(huge_zero_page_shrinker); | |
481 | ||
482 | deferred_split_shrinker->count_objects = deferred_split_count; | |
483 | deferred_split_shrinker->scan_objects = deferred_split_scan; | |
484 | shrinker_register(deferred_split_shrinker); | |
485 | ||
486 | return 0; | |
487 | } | |
488 | ||
489 | static void __init thp_shrinker_exit(void) | |
490 | { | |
491 | shrinker_free(huge_zero_page_shrinker); | |
492 | shrinker_free(deferred_split_shrinker); | |
493 | } | |
494 | ||
569e5590 SL |
495 | static int __init hugepage_init(void) |
496 | { | |
497 | int err; | |
498 | struct kobject *hugepage_kobj; | |
499 | ||
500 | if (!has_transparent_hugepage()) { | |
3c556d24 | 501 | transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED; |
569e5590 SL |
502 | return -EINVAL; |
503 | } | |
504 | ||
ff20c2e0 KS |
505 | /* |
506 | * hugepages can't be allocated by the buddy allocator | |
507 | */ | |
23baf831 | 508 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER > MAX_ORDER); |
ff20c2e0 KS |
509 | /* |
510 | * we use page->mapping and page->index in second tail page | |
511 | * as list_head: assuming THP order >= 2 | |
512 | */ | |
513 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
514 | ||
569e5590 SL |
515 | err = hugepage_init_sysfs(&hugepage_kobj); |
516 | if (err) | |
65ebb64f | 517 | goto err_sysfs; |
ba76149f | 518 | |
b46e756f | 519 | err = khugepaged_init(); |
ba76149f | 520 | if (err) |
65ebb64f | 521 | goto err_slab; |
ba76149f | 522 | |
54d91729 | 523 | err = thp_shrinker_init(); |
9a982250 | 524 | if (err) |
54d91729 | 525 | goto err_shrinker; |
97ae1749 | 526 | |
97562cd2 RR |
527 | /* |
528 | * By default disable transparent hugepages on smaller systems, | |
529 | * where the extra memory used could hurt more than TLB overhead | |
530 | * is likely to save. The admin can still enable it through /sys. | |
531 | */ | |
ca79b0c2 | 532 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 533 | transparent_hugepage_flags = 0; |
79553da2 KS |
534 | return 0; |
535 | } | |
97562cd2 | 536 | |
79553da2 | 537 | err = start_stop_khugepaged(); |
65ebb64f KS |
538 | if (err) |
539 | goto err_khugepaged; | |
ba76149f | 540 | |
569e5590 | 541 | return 0; |
65ebb64f | 542 | err_khugepaged: |
54d91729 QZ |
543 | thp_shrinker_exit(); |
544 | err_shrinker: | |
b46e756f | 545 | khugepaged_destroy(); |
65ebb64f | 546 | err_slab: |
569e5590 | 547 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 548 | err_sysfs: |
ba76149f | 549 | return err; |
71e3aac0 | 550 | } |
a64fb3cd | 551 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
552 | |
553 | static int __init setup_transparent_hugepage(char *str) | |
554 | { | |
555 | int ret = 0; | |
556 | if (!str) | |
557 | goto out; | |
558 | if (!strcmp(str, "always")) { | |
559 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
560 | &transparent_hugepage_flags); | |
561 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
562 | &transparent_hugepage_flags); | |
563 | ret = 1; | |
564 | } else if (!strcmp(str, "madvise")) { | |
565 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
566 | &transparent_hugepage_flags); | |
567 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
568 | &transparent_hugepage_flags); | |
569 | ret = 1; | |
570 | } else if (!strcmp(str, "never")) { | |
571 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
572 | &transparent_hugepage_flags); | |
573 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
574 | &transparent_hugepage_flags); | |
575 | ret = 1; | |
576 | } | |
577 | out: | |
578 | if (!ret) | |
ae3a8c1c | 579 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
580 | return ret; |
581 | } | |
582 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
583 | ||
f55e1014 | 584 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 585 | { |
f55e1014 | 586 | if (likely(vma->vm_flags & VM_WRITE)) |
161e393c | 587 | pmd = pmd_mkwrite(pmd, vma); |
71e3aac0 AA |
588 | return pmd; |
589 | } | |
590 | ||
87eaceb3 | 591 | #ifdef CONFIG_MEMCG |
f8baa6be MWO |
592 | static inline |
593 | struct deferred_split *get_deferred_split_queue(struct folio *folio) | |
9a982250 | 594 | { |
f8baa6be MWO |
595 | struct mem_cgroup *memcg = folio_memcg(folio); |
596 | struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); | |
87eaceb3 YS |
597 | |
598 | if (memcg) | |
599 | return &memcg->deferred_split_queue; | |
600 | else | |
601 | return &pgdat->deferred_split_queue; | |
9a982250 | 602 | } |
87eaceb3 | 603 | #else |
f8baa6be MWO |
604 | static inline |
605 | struct deferred_split *get_deferred_split_queue(struct folio *folio) | |
87eaceb3 | 606 | { |
f8baa6be | 607 | struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); |
87eaceb3 YS |
608 | |
609 | return &pgdat->deferred_split_queue; | |
610 | } | |
611 | #endif | |
9a982250 | 612 | |
da6e7bf3 | 613 | void folio_prep_large_rmappable(struct folio *folio) |
9a982250 | 614 | { |
8991de90 MWO |
615 | VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); |
616 | INIT_LIST_HEAD(&folio->_deferred_list); | |
de53c05f | 617 | folio_set_large_rmappable(folio); |
9a982250 KS |
618 | } |
619 | ||
a644b0ab | 620 | static inline bool is_transparent_hugepage(struct folio *folio) |
005ba37c | 621 | { |
a644b0ab | 622 | if (!folio_test_large(folio)) |
fa1f68cc | 623 | return false; |
005ba37c | 624 | |
f04029f3 | 625 | return is_huge_zero_page(&folio->page) || |
de53c05f | 626 | folio_test_large_rmappable(folio); |
005ba37c | 627 | } |
005ba37c | 628 | |
97d3d0f9 KS |
629 | static unsigned long __thp_get_unmapped_area(struct file *filp, |
630 | unsigned long addr, unsigned long len, | |
74d2fad1 TK |
631 | loff_t off, unsigned long flags, unsigned long size) |
632 | { | |
74d2fad1 TK |
633 | loff_t off_end = off + len; |
634 | loff_t off_align = round_up(off, size); | |
97d3d0f9 | 635 | unsigned long len_pad, ret; |
74d2fad1 TK |
636 | |
637 | if (off_end <= off_align || (off_end - off_align) < size) | |
638 | return 0; | |
639 | ||
640 | len_pad = len + size; | |
641 | if (len_pad < len || (off + len_pad) < off) | |
642 | return 0; | |
643 | ||
97d3d0f9 | 644 | ret = current->mm->get_unmapped_area(filp, addr, len_pad, |
74d2fad1 | 645 | off >> PAGE_SHIFT, flags); |
97d3d0f9 KS |
646 | |
647 | /* | |
648 | * The failure might be due to length padding. The caller will retry | |
649 | * without the padding. | |
650 | */ | |
651 | if (IS_ERR_VALUE(ret)) | |
74d2fad1 TK |
652 | return 0; |
653 | ||
97d3d0f9 KS |
654 | /* |
655 | * Do not try to align to THP boundary if allocation at the address | |
656 | * hint succeeds. | |
657 | */ | |
658 | if (ret == addr) | |
659 | return addr; | |
660 | ||
661 | ret += (off - ret) & (size - 1); | |
662 | return ret; | |
74d2fad1 TK |
663 | } |
664 | ||
665 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
666 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
667 | { | |
97d3d0f9 | 668 | unsigned long ret; |
74d2fad1 TK |
669 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; |
670 | ||
97d3d0f9 KS |
671 | ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); |
672 | if (ret) | |
673 | return ret; | |
1854bc6e | 674 | |
74d2fad1 TK |
675 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); |
676 | } | |
677 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
678 | ||
2b740303 SJ |
679 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
680 | struct page *page, gfp_t gfp) | |
71e3aac0 | 681 | { |
82b0f8c3 | 682 | struct vm_area_struct *vma = vmf->vma; |
cfe3236d | 683 | struct folio *folio = page_folio(page); |
71e3aac0 | 684 | pgtable_t pgtable; |
82b0f8c3 | 685 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 686 | vm_fault_t ret = 0; |
71e3aac0 | 687 | |
cfe3236d | 688 | VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); |
00501b53 | 689 | |
cfe3236d KW |
690 | if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) { |
691 | folio_put(folio); | |
6b251fc9 | 692 | count_vm_event(THP_FAULT_FALLBACK); |
85b9f46e | 693 | count_vm_event(THP_FAULT_FALLBACK_CHARGE); |
6b251fc9 AA |
694 | return VM_FAULT_FALLBACK; |
695 | } | |
cfe3236d | 696 | folio_throttle_swaprate(folio, gfp); |
00501b53 | 697 | |
4cf58924 | 698 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 699 | if (unlikely(!pgtable)) { |
6b31d595 MH |
700 | ret = VM_FAULT_OOM; |
701 | goto release; | |
00501b53 | 702 | } |
71e3aac0 | 703 | |
c79b57e4 | 704 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 | 705 | /* |
cfe3236d | 706 | * The memory barrier inside __folio_mark_uptodate makes sure that |
52f37629 MK |
707 | * clear_huge_page writes become visible before the set_pmd_at() |
708 | * write. | |
709 | */ | |
cfe3236d | 710 | __folio_mark_uptodate(folio); |
71e3aac0 | 711 | |
82b0f8c3 JK |
712 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
713 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 714 | goto unlock_release; |
71e3aac0 AA |
715 | } else { |
716 | pmd_t entry; | |
6b251fc9 | 717 | |
6b31d595 MH |
718 | ret = check_stable_address_space(vma->vm_mm); |
719 | if (ret) | |
720 | goto unlock_release; | |
721 | ||
6b251fc9 AA |
722 | /* Deliver the page fault to userland */ |
723 | if (userfaultfd_missing(vma)) { | |
82b0f8c3 | 724 | spin_unlock(vmf->ptl); |
cfe3236d | 725 | folio_put(folio); |
bae473a4 | 726 | pte_free(vma->vm_mm, pgtable); |
8fd5eda4 ML |
727 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
728 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); | |
729 | return ret; | |
6b251fc9 AA |
730 | } |
731 | ||
3122359a | 732 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 733 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
cfe3236d KW |
734 | folio_add_new_anon_rmap(folio, vma, haddr); |
735 | folio_add_lru_vma(folio, vma); | |
82b0f8c3 JK |
736 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
737 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
fca40573 | 738 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
bae473a4 | 739 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 740 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 741 | spin_unlock(vmf->ptl); |
6b251fc9 | 742 | count_vm_event(THP_FAULT_ALLOC); |
9d82c694 | 743 | count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); |
71e3aac0 AA |
744 | } |
745 | ||
aa2e878e | 746 | return 0; |
6b31d595 MH |
747 | unlock_release: |
748 | spin_unlock(vmf->ptl); | |
749 | release: | |
750 | if (pgtable) | |
751 | pte_free(vma->vm_mm, pgtable); | |
cfe3236d | 752 | folio_put(folio); |
6b31d595 MH |
753 | return ret; |
754 | ||
71e3aac0 AA |
755 | } |
756 | ||
444eb2a4 | 757 | /* |
21440d7e DR |
758 | * always: directly stall for all thp allocations |
759 | * defer: wake kswapd and fail if not immediately available | |
760 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
761 | * fail if not immediately available | |
762 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
763 | * available | |
764 | * never: never stall for any thp allocation | |
444eb2a4 | 765 | */ |
164cc4fe | 766 | gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) |
444eb2a4 | 767 | { |
164cc4fe | 768 | const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); |
2f0799a0 | 769 | |
ac79f78d | 770 | /* Always do synchronous compaction */ |
a8282608 AA |
771 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
772 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); | |
ac79f78d DR |
773 | |
774 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 775 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
19deb769 | 776 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
ac79f78d DR |
777 | |
778 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 779 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
780 | return GFP_TRANSHUGE_LIGHT | |
781 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
782 | __GFP_KSWAPD_RECLAIM); | |
ac79f78d DR |
783 | |
784 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 785 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
786 | return GFP_TRANSHUGE_LIGHT | |
787 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
ac79f78d | 788 | |
19deb769 | 789 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
790 | } |
791 | ||
c4088ebd | 792 | /* Caller must hold page table lock. */ |
2efeb8da | 793 | static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 794 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 795 | struct page *zero_page) |
fc9fe822 KS |
796 | { |
797 | pmd_t entry; | |
7c414164 | 798 | if (!pmd_none(*pmd)) |
2efeb8da | 799 | return; |
5918d10a | 800 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 801 | entry = pmd_mkhuge(entry); |
c8bb4163 | 802 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
fc9fe822 | 803 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 804 | mm_inc_nr_ptes(mm); |
fc9fe822 KS |
805 | } |
806 | ||
2b740303 | 807 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 808 | { |
82b0f8c3 | 809 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 810 | gfp_t gfp; |
cb196ee1 | 811 | struct folio *folio; |
82b0f8c3 | 812 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 813 | |
43675e6f | 814 | if (!transhuge_vma_suitable(vma, haddr)) |
c0292554 | 815 | return VM_FAULT_FALLBACK; |
128ec037 KS |
816 | if (unlikely(anon_vma_prepare(vma))) |
817 | return VM_FAULT_OOM; | |
4fa6893f | 818 | khugepaged_enter_vma(vma, vma->vm_flags); |
d2081b2b | 819 | |
82b0f8c3 | 820 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 821 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
822 | transparent_hugepage_use_zero_page()) { |
823 | pgtable_t pgtable; | |
824 | struct page *zero_page; | |
2b740303 | 825 | vm_fault_t ret; |
4cf58924 | 826 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 827 | if (unlikely(!pgtable)) |
ba76149f | 828 | return VM_FAULT_OOM; |
6fcb52a5 | 829 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 830 | if (unlikely(!zero_page)) { |
bae473a4 | 831 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 832 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 833 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 834 | } |
82b0f8c3 | 835 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 | 836 | ret = 0; |
82b0f8c3 | 837 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
838 | ret = check_stable_address_space(vma->vm_mm); |
839 | if (ret) { | |
840 | spin_unlock(vmf->ptl); | |
bfe8cc1d | 841 | pte_free(vma->vm_mm, pgtable); |
6b31d595 | 842 | } else if (userfaultfd_missing(vma)) { |
82b0f8c3 | 843 | spin_unlock(vmf->ptl); |
bfe8cc1d | 844 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 845 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
846 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
847 | } else { | |
bae473a4 | 848 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 | 849 | haddr, vmf->pmd, zero_page); |
fca40573 | 850 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 851 | spin_unlock(vmf->ptl); |
6b251fc9 | 852 | } |
bfe8cc1d | 853 | } else { |
82b0f8c3 | 854 | spin_unlock(vmf->ptl); |
bae473a4 | 855 | pte_free(vma->vm_mm, pgtable); |
bfe8cc1d | 856 | } |
6b251fc9 | 857 | return ret; |
71e3aac0 | 858 | } |
164cc4fe | 859 | gfp = vma_thp_gfp_mask(vma); |
cb196ee1 MWO |
860 | folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true); |
861 | if (unlikely(!folio)) { | |
128ec037 | 862 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 863 | return VM_FAULT_FALLBACK; |
128ec037 | 864 | } |
cb196ee1 | 865 | return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp); |
71e3aac0 AA |
866 | } |
867 | ||
ae18d6dc | 868 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
869 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
870 | pgtable_t pgtable) | |
5cad465d MW |
871 | { |
872 | struct mm_struct *mm = vma->vm_mm; | |
873 | pmd_t entry; | |
874 | spinlock_t *ptl; | |
875 | ||
876 | ptl = pmd_lock(mm, pmd); | |
c6f3c5ee AK |
877 | if (!pmd_none(*pmd)) { |
878 | if (write) { | |
879 | if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { | |
880 | WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); | |
881 | goto out_unlock; | |
882 | } | |
883 | entry = pmd_mkyoung(*pmd); | |
884 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
885 | if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) | |
886 | update_mmu_cache_pmd(vma, addr, pmd); | |
887 | } | |
888 | ||
889 | goto out_unlock; | |
890 | } | |
891 | ||
f25748e3 DW |
892 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
893 | if (pfn_t_devmap(pfn)) | |
894 | entry = pmd_mkdevmap(entry); | |
01871e59 | 895 | if (write) { |
f55e1014 LT |
896 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
897 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 898 | } |
3b6521f5 OH |
899 | |
900 | if (pgtable) { | |
901 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 902 | mm_inc_nr_ptes(mm); |
c6f3c5ee | 903 | pgtable = NULL; |
3b6521f5 OH |
904 | } |
905 | ||
01871e59 RZ |
906 | set_pmd_at(mm, addr, pmd, entry); |
907 | update_mmu_cache_pmd(vma, addr, pmd); | |
c6f3c5ee AK |
908 | |
909 | out_unlock: | |
5cad465d | 910 | spin_unlock(ptl); |
c6f3c5ee AK |
911 | if (pgtable) |
912 | pte_free(mm, pgtable); | |
5cad465d MW |
913 | } |
914 | ||
9a9731b1 | 915 | /** |
7b806d22 | 916 | * vmf_insert_pfn_pmd - insert a pmd size pfn |
9a9731b1 THV |
917 | * @vmf: Structure describing the fault |
918 | * @pfn: pfn to insert | |
9a9731b1 THV |
919 | * @write: whether it's a write fault |
920 | * | |
7b806d22 | 921 | * Insert a pmd size pfn. See vmf_insert_pfn() for additional info. |
9a9731b1 THV |
922 | * |
923 | * Return: vm_fault_t value. | |
924 | */ | |
7b806d22 | 925 | vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) |
5cad465d | 926 | { |
fce86ff5 DW |
927 | unsigned long addr = vmf->address & PMD_MASK; |
928 | struct vm_area_struct *vma = vmf->vma; | |
7b806d22 | 929 | pgprot_t pgprot = vma->vm_page_prot; |
3b6521f5 | 930 | pgtable_t pgtable = NULL; |
fce86ff5 | 931 | |
5cad465d MW |
932 | /* |
933 | * If we had pmd_special, we could avoid all these restrictions, | |
934 | * but we need to be consistent with PTEs and architectures that | |
935 | * can't support a 'special' bit. | |
936 | */ | |
e1fb4a08 DJ |
937 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
938 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
939 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
940 | (VM_PFNMAP|VM_MIXEDMAP)); | |
941 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
942 | |
943 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
944 | return VM_FAULT_SIGBUS; | |
308a047c | 945 | |
3b6521f5 | 946 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 947 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
948 | if (!pgtable) |
949 | return VM_FAULT_OOM; | |
950 | } | |
951 | ||
308a047c BP |
952 | track_pfn_insert(vma, &pgprot, pfn); |
953 | ||
fce86ff5 | 954 | insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 955 | return VM_FAULT_NOPAGE; |
5cad465d | 956 | } |
7b806d22 | 957 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); |
5cad465d | 958 | |
a00cc7d9 | 959 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 960 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 961 | { |
f55e1014 | 962 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
963 | pud = pud_mkwrite(pud); |
964 | return pud; | |
965 | } | |
966 | ||
967 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
7b806d22 | 968 | pud_t *pud, pfn_t pfn, bool write) |
a00cc7d9 MW |
969 | { |
970 | struct mm_struct *mm = vma->vm_mm; | |
7b806d22 | 971 | pgprot_t prot = vma->vm_page_prot; |
a00cc7d9 MW |
972 | pud_t entry; |
973 | spinlock_t *ptl; | |
974 | ||
975 | ptl = pud_lock(mm, pud); | |
c6f3c5ee AK |
976 | if (!pud_none(*pud)) { |
977 | if (write) { | |
978 | if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { | |
979 | WARN_ON_ONCE(!is_huge_zero_pud(*pud)); | |
980 | goto out_unlock; | |
981 | } | |
982 | entry = pud_mkyoung(*pud); | |
983 | entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); | |
984 | if (pudp_set_access_flags(vma, addr, pud, entry, 1)) | |
985 | update_mmu_cache_pud(vma, addr, pud); | |
986 | } | |
987 | goto out_unlock; | |
988 | } | |
989 | ||
a00cc7d9 MW |
990 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); |
991 | if (pfn_t_devmap(pfn)) | |
992 | entry = pud_mkdevmap(entry); | |
993 | if (write) { | |
f55e1014 LT |
994 | entry = pud_mkyoung(pud_mkdirty(entry)); |
995 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
996 | } |
997 | set_pud_at(mm, addr, pud, entry); | |
998 | update_mmu_cache_pud(vma, addr, pud); | |
c6f3c5ee AK |
999 | |
1000 | out_unlock: | |
a00cc7d9 MW |
1001 | spin_unlock(ptl); |
1002 | } | |
1003 | ||
9a9731b1 | 1004 | /** |
7b806d22 | 1005 | * vmf_insert_pfn_pud - insert a pud size pfn |
9a9731b1 THV |
1006 | * @vmf: Structure describing the fault |
1007 | * @pfn: pfn to insert | |
9a9731b1 THV |
1008 | * @write: whether it's a write fault |
1009 | * | |
7b806d22 | 1010 | * Insert a pud size pfn. See vmf_insert_pfn() for additional info. |
9a9731b1 THV |
1011 | * |
1012 | * Return: vm_fault_t value. | |
1013 | */ | |
7b806d22 | 1014 | vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) |
a00cc7d9 | 1015 | { |
fce86ff5 DW |
1016 | unsigned long addr = vmf->address & PUD_MASK; |
1017 | struct vm_area_struct *vma = vmf->vma; | |
7b806d22 | 1018 | pgprot_t pgprot = vma->vm_page_prot; |
fce86ff5 | 1019 | |
a00cc7d9 MW |
1020 | /* |
1021 | * If we had pud_special, we could avoid all these restrictions, | |
1022 | * but we need to be consistent with PTEs and architectures that | |
1023 | * can't support a 'special' bit. | |
1024 | */ | |
62ec0d8c DJ |
1025 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
1026 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
1027 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
1028 | (VM_PFNMAP|VM_MIXEDMAP)); | |
1029 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
1030 | |
1031 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
1032 | return VM_FAULT_SIGBUS; | |
1033 | ||
1034 | track_pfn_insert(vma, &pgprot, pfn); | |
1035 | ||
7b806d22 | 1036 | insert_pfn_pud(vma, addr, vmf->pud, pfn, write); |
a00cc7d9 MW |
1037 | return VM_FAULT_NOPAGE; |
1038 | } | |
7b806d22 | 1039 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); |
a00cc7d9 MW |
1040 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ |
1041 | ||
3565fce3 | 1042 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a69e4717 | 1043 | pmd_t *pmd, bool write) |
3565fce3 DW |
1044 | { |
1045 | pmd_t _pmd; | |
1046 | ||
a8f97366 | 1047 | _pmd = pmd_mkyoung(*pmd); |
a69e4717 | 1048 | if (write) |
a8f97366 | 1049 | _pmd = pmd_mkdirty(_pmd); |
3565fce3 | 1050 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a69e4717 | 1051 | pmd, _pmd, write)) |
3565fce3 DW |
1052 | update_mmu_cache_pmd(vma, addr, pmd); |
1053 | } | |
1054 | ||
1055 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1056 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
1057 | { |
1058 | unsigned long pfn = pmd_pfn(*pmd); | |
1059 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 | 1060 | struct page *page; |
0f089235 | 1061 | int ret; |
3565fce3 DW |
1062 | |
1063 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
1064 | ||
f6f37321 | 1065 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
1066 | return NULL; |
1067 | ||
1068 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
1069 | /* pass */; | |
1070 | else | |
1071 | return NULL; | |
1072 | ||
1073 | if (flags & FOLL_TOUCH) | |
a69e4717 | 1074 | touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); |
3565fce3 DW |
1075 | |
1076 | /* | |
1077 | * device mapped pages can only be returned if the | |
1078 | * caller will manage the page reference count. | |
1079 | */ | |
3faa52c0 | 1080 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
3565fce3 DW |
1081 | return ERR_PTR(-EEXIST); |
1082 | ||
1083 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1084 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1085 | if (!*pgmap) | |
3565fce3 DW |
1086 | return ERR_PTR(-EFAULT); |
1087 | page = pfn_to_page(pfn); | |
0f089235 LG |
1088 | ret = try_grab_page(page, flags); |
1089 | if (ret) | |
1090 | page = ERR_PTR(ret); | |
3565fce3 DW |
1091 | |
1092 | return page; | |
1093 | } | |
1094 | ||
71e3aac0 AA |
1095 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
1096 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
8f34f1ea | 1097 | struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) |
71e3aac0 | 1098 | { |
c4088ebd | 1099 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
1100 | struct page *src_page; |
1101 | pmd_t pmd; | |
12c9d70b | 1102 | pgtable_t pgtable = NULL; |
628d47ce | 1103 | int ret = -ENOMEM; |
71e3aac0 | 1104 | |
628d47ce | 1105 | /* Skip if can be re-fill on fault */ |
8f34f1ea | 1106 | if (!vma_is_anonymous(dst_vma)) |
628d47ce KS |
1107 | return 0; |
1108 | ||
4cf58924 | 1109 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
1110 | if (unlikely(!pgtable)) |
1111 | goto out; | |
71e3aac0 | 1112 | |
c4088ebd KS |
1113 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
1114 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
1115 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
1116 | |
1117 | ret = -EAGAIN; | |
1118 | pmd = *src_pmd; | |
84c3fc4e ZY |
1119 | |
1120 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
1121 | if (unlikely(is_swap_pmd(pmd))) { | |
1122 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
1123 | ||
1124 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
6c287605 | 1125 | if (!is_readable_migration_entry(entry)) { |
4dd845b5 AP |
1126 | entry = make_readable_migration_entry( |
1127 | swp_offset(entry)); | |
84c3fc4e | 1128 | pmd = swp_entry_to_pmd(entry); |
ab6e3d09 NH |
1129 | if (pmd_swp_soft_dirty(*src_pmd)) |
1130 | pmd = pmd_swp_mksoft_dirty(pmd); | |
8f34f1ea PX |
1131 | if (pmd_swp_uffd_wp(*src_pmd)) |
1132 | pmd = pmd_swp_mkuffd_wp(pmd); | |
84c3fc4e ZY |
1133 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
1134 | } | |
dd8a67f9 | 1135 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 1136 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 1137 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
8f34f1ea PX |
1138 | if (!userfaultfd_wp(dst_vma)) |
1139 | pmd = pmd_swp_clear_uffd_wp(pmd); | |
84c3fc4e ZY |
1140 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
1141 | ret = 0; | |
1142 | goto out_unlock; | |
1143 | } | |
1144 | #endif | |
1145 | ||
628d47ce | 1146 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
1147 | pte_free(dst_mm, pgtable); |
1148 | goto out_unlock; | |
1149 | } | |
fc9fe822 | 1150 | /* |
c4088ebd | 1151 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
1152 | * under splitting since we don't split the page itself, only pmd to |
1153 | * a page table. | |
1154 | */ | |
1155 | if (is_huge_zero_pmd(pmd)) { | |
97ae1749 KS |
1156 | /* |
1157 | * get_huge_zero_page() will never allocate a new page here, | |
1158 | * since we already have a zero page to copy. It just takes a | |
1159 | * reference. | |
1160 | */ | |
5fc7a5f6 PX |
1161 | mm_get_huge_zero_page(dst_mm); |
1162 | goto out_zero_page; | |
fc9fe822 | 1163 | } |
de466bd6 | 1164 | |
628d47ce KS |
1165 | src_page = pmd_page(pmd); |
1166 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
d042035e | 1167 | |
fb3d824d DH |
1168 | get_page(src_page); |
1169 | if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { | |
1170 | /* Page maybe pinned: split and retry the fault on PTEs. */ | |
1171 | put_page(src_page); | |
d042035e PX |
1172 | pte_free(dst_mm, pgtable); |
1173 | spin_unlock(src_ptl); | |
1174 | spin_unlock(dst_ptl); | |
8f34f1ea | 1175 | __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); |
d042035e PX |
1176 | return -EAGAIN; |
1177 | } | |
628d47ce | 1178 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
5fc7a5f6 | 1179 | out_zero_page: |
c4812909 | 1180 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 1181 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 | 1182 | pmdp_set_wrprotect(src_mm, addr, src_pmd); |
8f34f1ea PX |
1183 | if (!userfaultfd_wp(dst_vma)) |
1184 | pmd = pmd_clear_uffd_wp(pmd); | |
71e3aac0 AA |
1185 | pmd = pmd_mkold(pmd_wrprotect(pmd)); |
1186 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
1187 | |
1188 | ret = 0; | |
1189 | out_unlock: | |
c4088ebd KS |
1190 | spin_unlock(src_ptl); |
1191 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1192 | out: |
1193 | return ret; | |
1194 | } | |
1195 | ||
a00cc7d9 MW |
1196 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1197 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
5fe653e9 | 1198 | pud_t *pud, bool write) |
a00cc7d9 MW |
1199 | { |
1200 | pud_t _pud; | |
1201 | ||
a8f97366 | 1202 | _pud = pud_mkyoung(*pud); |
5fe653e9 | 1203 | if (write) |
a8f97366 | 1204 | _pud = pud_mkdirty(_pud); |
a00cc7d9 | 1205 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
5fe653e9 | 1206 | pud, _pud, write)) |
a00cc7d9 MW |
1207 | update_mmu_cache_pud(vma, addr, pud); |
1208 | } | |
1209 | ||
1210 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1211 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1212 | { |
1213 | unsigned long pfn = pud_pfn(*pud); | |
1214 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 | 1215 | struct page *page; |
0f089235 | 1216 | int ret; |
a00cc7d9 MW |
1217 | |
1218 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1219 | ||
f6f37321 | 1220 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1221 | return NULL; |
1222 | ||
1223 | if (pud_present(*pud) && pud_devmap(*pud)) | |
1224 | /* pass */; | |
1225 | else | |
1226 | return NULL; | |
1227 | ||
1228 | if (flags & FOLL_TOUCH) | |
5fe653e9 | 1229 | touch_pud(vma, addr, pud, flags & FOLL_WRITE); |
a00cc7d9 MW |
1230 | |
1231 | /* | |
1232 | * device mapped pages can only be returned if the | |
1233 | * caller will manage the page reference count. | |
3faa52c0 JH |
1234 | * |
1235 | * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: | |
a00cc7d9 | 1236 | */ |
3faa52c0 | 1237 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
a00cc7d9 MW |
1238 | return ERR_PTR(-EEXIST); |
1239 | ||
1240 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1241 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1242 | if (!*pgmap) | |
a00cc7d9 MW |
1243 | return ERR_PTR(-EFAULT); |
1244 | page = pfn_to_page(pfn); | |
0f089235 LG |
1245 | |
1246 | ret = try_grab_page(page, flags); | |
1247 | if (ret) | |
1248 | page = ERR_PTR(ret); | |
a00cc7d9 MW |
1249 | |
1250 | return page; | |
1251 | } | |
1252 | ||
1253 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1254 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1255 | struct vm_area_struct *vma) | |
1256 | { | |
1257 | spinlock_t *dst_ptl, *src_ptl; | |
1258 | pud_t pud; | |
1259 | int ret; | |
1260 | ||
1261 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1262 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1263 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1264 | ||
1265 | ret = -EAGAIN; | |
1266 | pud = *src_pud; | |
1267 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1268 | goto out_unlock; | |
1269 | ||
1270 | /* | |
1271 | * When page table lock is held, the huge zero pud should not be | |
1272 | * under splitting since we don't split the page itself, only pud to | |
1273 | * a page table. | |
1274 | */ | |
1275 | if (is_huge_zero_pud(pud)) { | |
1276 | /* No huge zero pud yet */ | |
1277 | } | |
1278 | ||
fb3d824d DH |
1279 | /* |
1280 | * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() | |
1281 | * and split if duplicating fails. | |
1282 | */ | |
a00cc7d9 MW |
1283 | pudp_set_wrprotect(src_mm, addr, src_pud); |
1284 | pud = pud_mkold(pud_wrprotect(pud)); | |
1285 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1286 | ||
1287 | ret = 0; | |
1288 | out_unlock: | |
1289 | spin_unlock(src_ptl); | |
1290 | spin_unlock(dst_ptl); | |
1291 | return ret; | |
1292 | } | |
1293 | ||
1294 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1295 | { | |
a00cc7d9 MW |
1296 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
1297 | ||
1298 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1299 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1300 | goto unlock; | |
1301 | ||
5fe653e9 | 1302 | touch_pud(vmf->vma, vmf->address, vmf->pud, write); |
a00cc7d9 MW |
1303 | unlock: |
1304 | spin_unlock(vmf->ptl); | |
1305 | } | |
1306 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1307 | ||
5db4f15c | 1308 | void huge_pmd_set_accessed(struct vm_fault *vmf) |
a1dd450b | 1309 | { |
20f664aa | 1310 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1311 | |
82b0f8c3 | 1312 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
a69e4717 | 1313 | if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) |
a1dd450b WD |
1314 | goto unlock; |
1315 | ||
a69e4717 | 1316 | touch_pmd(vmf->vma, vmf->address, vmf->pmd, write); |
a1dd450b WD |
1317 | |
1318 | unlock: | |
82b0f8c3 | 1319 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1320 | } |
1321 | ||
5db4f15c | 1322 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) |
71e3aac0 | 1323 | { |
c89357e2 | 1324 | const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; |
82b0f8c3 | 1325 | struct vm_area_struct *vma = vmf->vma; |
2fad3d14 | 1326 | struct folio *folio; |
3917c802 | 1327 | struct page *page; |
82b0f8c3 | 1328 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
5db4f15c | 1329 | pmd_t orig_pmd = vmf->orig_pmd; |
71e3aac0 | 1330 | |
82b0f8c3 | 1331 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1332 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
3917c802 | 1333 | |
93b4796d | 1334 | if (is_huge_zero_pmd(orig_pmd)) |
3917c802 KS |
1335 | goto fallback; |
1336 | ||
82b0f8c3 | 1337 | spin_lock(vmf->ptl); |
3917c802 KS |
1338 | |
1339 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1340 | spin_unlock(vmf->ptl); | |
1341 | return 0; | |
1342 | } | |
71e3aac0 AA |
1343 | |
1344 | page = pmd_page(orig_pmd); | |
2fad3d14 | 1345 | folio = page_folio(page); |
f6004e73 | 1346 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3917c802 | 1347 | |
6c287605 DH |
1348 | /* Early check when only holding the PT lock. */ |
1349 | if (PageAnonExclusive(page)) | |
1350 | goto reuse; | |
1351 | ||
2fad3d14 MWO |
1352 | if (!folio_trylock(folio)) { |
1353 | folio_get(folio); | |
ba3c4ce6 | 1354 | spin_unlock(vmf->ptl); |
2fad3d14 | 1355 | folio_lock(folio); |
ba3c4ce6 HY |
1356 | spin_lock(vmf->ptl); |
1357 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
3917c802 | 1358 | spin_unlock(vmf->ptl); |
2fad3d14 MWO |
1359 | folio_unlock(folio); |
1360 | folio_put(folio); | |
3917c802 | 1361 | return 0; |
ba3c4ce6 | 1362 | } |
2fad3d14 | 1363 | folio_put(folio); |
ba3c4ce6 | 1364 | } |
3917c802 | 1365 | |
6c287605 DH |
1366 | /* Recheck after temporarily dropping the PT lock. */ |
1367 | if (PageAnonExclusive(page)) { | |
2fad3d14 | 1368 | folio_unlock(folio); |
6c287605 DH |
1369 | goto reuse; |
1370 | } | |
1371 | ||
3917c802 | 1372 | /* |
2fad3d14 MWO |
1373 | * See do_wp_page(): we can only reuse the folio exclusively if |
1374 | * there are no additional references. Note that we always drain | |
1fec6890 | 1375 | * the LRU cache immediately after adding a THP. |
3917c802 | 1376 | */ |
2fad3d14 MWO |
1377 | if (folio_ref_count(folio) > |
1378 | 1 + folio_test_swapcache(folio) * folio_nr_pages(folio)) | |
3bff7e3f | 1379 | goto unlock_fallback; |
2fad3d14 MWO |
1380 | if (folio_test_swapcache(folio)) |
1381 | folio_free_swap(folio); | |
1382 | if (folio_ref_count(folio) == 1) { | |
71e3aac0 | 1383 | pmd_t entry; |
6c54dc6c | 1384 | |
06968625 | 1385 | folio_move_anon_rmap(folio, vma); |
5ca43289 | 1386 | SetPageAnonExclusive(page); |
2fad3d14 | 1387 | folio_unlock(folio); |
6c287605 | 1388 | reuse: |
c89357e2 DH |
1389 | if (unlikely(unshare)) { |
1390 | spin_unlock(vmf->ptl); | |
1391 | return 0; | |
1392 | } | |
71e3aac0 | 1393 | entry = pmd_mkyoung(orig_pmd); |
f55e1014 | 1394 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
3917c802 | 1395 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
82b0f8c3 | 1396 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 1397 | spin_unlock(vmf->ptl); |
cb8d8633 | 1398 | return 0; |
71e3aac0 | 1399 | } |
3917c802 | 1400 | |
3bff7e3f | 1401 | unlock_fallback: |
2fad3d14 | 1402 | folio_unlock(folio); |
82b0f8c3 | 1403 | spin_unlock(vmf->ptl); |
3917c802 KS |
1404 | fallback: |
1405 | __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); | |
1406 | return VM_FAULT_FALLBACK; | |
71e3aac0 AA |
1407 | } |
1408 | ||
c27f479e DH |
1409 | static inline bool can_change_pmd_writable(struct vm_area_struct *vma, |
1410 | unsigned long addr, pmd_t pmd) | |
1411 | { | |
1412 | struct page *page; | |
1413 | ||
1414 | if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE))) | |
1415 | return false; | |
1416 | ||
1417 | /* Don't touch entries that are not even readable (NUMA hinting). */ | |
1418 | if (pmd_protnone(pmd)) | |
1419 | return false; | |
1420 | ||
1421 | /* Do we need write faults for softdirty tracking? */ | |
1422 | if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) | |
1423 | return false; | |
1424 | ||
1425 | /* Do we need write faults for uffd-wp tracking? */ | |
1426 | if (userfaultfd_huge_pmd_wp(vma, pmd)) | |
1427 | return false; | |
1428 | ||
1429 | if (!(vma->vm_flags & VM_SHARED)) { | |
1430 | /* See can_change_pte_writable(). */ | |
1431 | page = vm_normal_page_pmd(vma, addr, pmd); | |
1432 | return page && PageAnon(page) && PageAnonExclusive(page); | |
1433 | } | |
1434 | ||
1435 | /* See can_change_pte_writable(). */ | |
1436 | return pmd_dirty(pmd); | |
1437 | } | |
1438 | ||
5535be30 DH |
1439 | /* FOLL_FORCE can write to even unwritable PMDs in COW mappings. */ |
1440 | static inline bool can_follow_write_pmd(pmd_t pmd, struct page *page, | |
1441 | struct vm_area_struct *vma, | |
1442 | unsigned int flags) | |
8310d48b | 1443 | { |
5535be30 DH |
1444 | /* If the pmd is writable, we can write to the page. */ |
1445 | if (pmd_write(pmd)) | |
1446 | return true; | |
1447 | ||
1448 | /* Maybe FOLL_FORCE is set to override it? */ | |
1449 | if (!(flags & FOLL_FORCE)) | |
1450 | return false; | |
1451 | ||
1452 | /* But FOLL_FORCE has no effect on shared mappings */ | |
1453 | if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED)) | |
1454 | return false; | |
1455 | ||
1456 | /* ... or read-only private ones */ | |
1457 | if (!(vma->vm_flags & VM_MAYWRITE)) | |
1458 | return false; | |
1459 | ||
1460 | /* ... or already writable ones that just need to take a write fault */ | |
1461 | if (vma->vm_flags & VM_WRITE) | |
1462 | return false; | |
1463 | ||
1464 | /* | |
1465 | * See can_change_pte_writable(): we broke COW and could map the page | |
1466 | * writable if we have an exclusive anonymous page ... | |
1467 | */ | |
1468 | if (!page || !PageAnon(page) || !PageAnonExclusive(page)) | |
1469 | return false; | |
1470 | ||
1471 | /* ... and a write-fault isn't required for other reasons. */ | |
1472 | if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) | |
1473 | return false; | |
1474 | return !userfaultfd_huge_pmd_wp(vma, pmd); | |
8310d48b KF |
1475 | } |
1476 | ||
b676b293 | 1477 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1478 | unsigned long addr, |
1479 | pmd_t *pmd, | |
1480 | unsigned int flags) | |
1481 | { | |
b676b293 | 1482 | struct mm_struct *mm = vma->vm_mm; |
5535be30 | 1483 | struct page *page; |
0f089235 | 1484 | int ret; |
71e3aac0 | 1485 | |
c4088ebd | 1486 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1487 | |
5535be30 DH |
1488 | page = pmd_page(*pmd); |
1489 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); | |
1490 | ||
1491 | if ((flags & FOLL_WRITE) && | |
1492 | !can_follow_write_pmd(*pmd, page, vma, flags)) | |
1493 | return NULL; | |
71e3aac0 | 1494 | |
85facf25 KS |
1495 | /* Avoid dumping huge zero page */ |
1496 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1497 | return ERR_PTR(-EFAULT); | |
1498 | ||
d74943a2 | 1499 | if (pmd_protnone(*pmd) && !gup_can_follow_protnone(vma, flags)) |
5535be30 | 1500 | return NULL; |
3faa52c0 | 1501 | |
84209e87 | 1502 | if (!pmd_write(*pmd) && gup_must_unshare(vma, flags, page)) |
a7f22660 DH |
1503 | return ERR_PTR(-EMLINK); |
1504 | ||
b6a2619c DH |
1505 | VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && |
1506 | !PageAnonExclusive(page), page); | |
1507 | ||
0f089235 LG |
1508 | ret = try_grab_page(page, flags); |
1509 | if (ret) | |
1510 | return ERR_PTR(ret); | |
3faa52c0 | 1511 | |
3565fce3 | 1512 | if (flags & FOLL_TOUCH) |
a69e4717 | 1513 | touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); |
3faa52c0 | 1514 | |
71e3aac0 | 1515 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1516 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1517 | |
71e3aac0 AA |
1518 | return page; |
1519 | } | |
1520 | ||
d10e63f2 | 1521 | /* NUMA hinting page fault entry point for trans huge pmds */ |
5db4f15c | 1522 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) |
d10e63f2 | 1523 | { |
82b0f8c3 | 1524 | struct vm_area_struct *vma = vmf->vma; |
c5b5a3dd YS |
1525 | pmd_t oldpmd = vmf->orig_pmd; |
1526 | pmd_t pmd; | |
667ffc31 | 1527 | struct folio *folio; |
82b0f8c3 | 1528 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
667ffc31 | 1529 | int nid = NUMA_NO_NODE; |
33024536 | 1530 | int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK); |
6a56ccbc | 1531 | bool migrated = false, writable = false; |
6688cc05 | 1532 | int flags = 0; |
d10e63f2 | 1533 | |
82b0f8c3 | 1534 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
c5b5a3dd | 1535 | if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { |
82b0f8c3 | 1536 | spin_unlock(vmf->ptl); |
de466bd6 MG |
1537 | goto out; |
1538 | } | |
1539 | ||
c5b5a3dd | 1540 | pmd = pmd_modify(oldpmd, vma->vm_page_prot); |
6a56ccbc DH |
1541 | |
1542 | /* | |
1543 | * Detect now whether the PMD could be writable; this information | |
1544 | * is only valid while holding the PT lock. | |
1545 | */ | |
1546 | writable = pmd_write(pmd); | |
1547 | if (!writable && vma_wants_manual_pte_write_upgrade(vma) && | |
1548 | can_change_pmd_writable(vma, vmf->address, pmd)) | |
1549 | writable = true; | |
1550 | ||
667ffc31 KW |
1551 | folio = vm_normal_folio_pmd(vma, haddr, pmd); |
1552 | if (!folio) | |
c5b5a3dd YS |
1553 | goto out_map; |
1554 | ||
1555 | /* See similar comment in do_numa_page for explanation */ | |
6a56ccbc | 1556 | if (!writable) |
c5b5a3dd YS |
1557 | flags |= TNF_NO_GROUP; |
1558 | ||
667ffc31 | 1559 | nid = folio_nid(folio); |
33024536 HY |
1560 | /* |
1561 | * For memory tiering mode, cpupid of slow memory page is used | |
1562 | * to record page access time. So use default value. | |
1563 | */ | |
667ffc31 | 1564 | if (node_is_toptier(nid)) |
c4a8d2fa | 1565 | last_cpupid = folio_last_cpupid(folio); |
cda6d936 | 1566 | target_nid = numa_migrate_prep(folio, vma, haddr, nid, &flags); |
c5b5a3dd | 1567 | if (target_nid == NUMA_NO_NODE) { |
667ffc31 | 1568 | folio_put(folio); |
c5b5a3dd YS |
1569 | goto out_map; |
1570 | } | |
1571 | ||
82b0f8c3 | 1572 | spin_unlock(vmf->ptl); |
6a56ccbc | 1573 | writable = false; |
8b1b436d | 1574 | |
667ffc31 | 1575 | migrated = migrate_misplaced_folio(folio, vma, target_nid); |
6688cc05 PZ |
1576 | if (migrated) { |
1577 | flags |= TNF_MIGRATED; | |
667ffc31 | 1578 | nid = target_nid; |
c5b5a3dd | 1579 | } else { |
074c2381 | 1580 | flags |= TNF_MIGRATE_FAIL; |
c5b5a3dd YS |
1581 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1582 | if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { | |
1583 | spin_unlock(vmf->ptl); | |
1584 | goto out; | |
1585 | } | |
1586 | goto out_map; | |
1587 | } | |
b8916634 MG |
1588 | |
1589 | out: | |
667ffc31 KW |
1590 | if (nid != NUMA_NO_NODE) |
1591 | task_numa_fault(last_cpupid, nid, HPAGE_PMD_NR, flags); | |
8191acbd | 1592 | |
d10e63f2 | 1593 | return 0; |
c5b5a3dd YS |
1594 | |
1595 | out_map: | |
1596 | /* Restore the PMD */ | |
1597 | pmd = pmd_modify(oldpmd, vma->vm_page_prot); | |
1598 | pmd = pmd_mkyoung(pmd); | |
6a56ccbc | 1599 | if (writable) |
161e393c | 1600 | pmd = pmd_mkwrite(pmd, vma); |
c5b5a3dd YS |
1601 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1602 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
1603 | spin_unlock(vmf->ptl); | |
1604 | goto out; | |
d10e63f2 MG |
1605 | } |
1606 | ||
319904ad HY |
1607 | /* |
1608 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1609 | * Otherwise, return false. | |
1610 | */ | |
1611 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1612 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1613 | { |
1614 | spinlock_t *ptl; | |
1615 | pmd_t orig_pmd; | |
fc986a38 | 1616 | struct folio *folio; |
b8d3c4c3 | 1617 | struct mm_struct *mm = tlb->mm; |
319904ad | 1618 | bool ret = false; |
b8d3c4c3 | 1619 | |
ed6a7935 | 1620 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1621 | |
b6ec57f4 KS |
1622 | ptl = pmd_trans_huge_lock(pmd, vma); |
1623 | if (!ptl) | |
25eedabe | 1624 | goto out_unlocked; |
b8d3c4c3 MK |
1625 | |
1626 | orig_pmd = *pmd; | |
319904ad | 1627 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1628 | goto out; |
b8d3c4c3 | 1629 | |
84c3fc4e ZY |
1630 | if (unlikely(!pmd_present(orig_pmd))) { |
1631 | VM_BUG_ON(thp_migration_supported() && | |
1632 | !is_pmd_migration_entry(orig_pmd)); | |
1633 | goto out; | |
1634 | } | |
1635 | ||
fc986a38 | 1636 | folio = pfn_folio(pmd_pfn(orig_pmd)); |
b8d3c4c3 | 1637 | /* |
fc986a38 KW |
1638 | * If other processes are mapping this folio, we couldn't discard |
1639 | * the folio unless they all do MADV_FREE so let's skip the folio. | |
b8d3c4c3 | 1640 | */ |
20b18aad | 1641 | if (folio_estimated_sharers(folio) != 1) |
b8d3c4c3 MK |
1642 | goto out; |
1643 | ||
fc986a38 | 1644 | if (!folio_trylock(folio)) |
b8d3c4c3 MK |
1645 | goto out; |
1646 | ||
1647 | /* | |
1648 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1649 | * will deactivate only them. | |
1650 | */ | |
1651 | if (next - addr != HPAGE_PMD_SIZE) { | |
fc986a38 | 1652 | folio_get(folio); |
b8d3c4c3 | 1653 | spin_unlock(ptl); |
fc986a38 KW |
1654 | split_folio(folio); |
1655 | folio_unlock(folio); | |
1656 | folio_put(folio); | |
b8d3c4c3 MK |
1657 | goto out_unlocked; |
1658 | } | |
1659 | ||
fc986a38 KW |
1660 | if (folio_test_dirty(folio)) |
1661 | folio_clear_dirty(folio); | |
1662 | folio_unlock(folio); | |
b8d3c4c3 | 1663 | |
b8d3c4c3 | 1664 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1665 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1666 | orig_pmd = pmd_mkold(orig_pmd); |
1667 | orig_pmd = pmd_mkclean(orig_pmd); | |
1668 | ||
1669 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1670 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1671 | } | |
802a3a92 | 1672 | |
6a6fe9eb | 1673 | folio_mark_lazyfree(folio); |
319904ad | 1674 | ret = true; |
b8d3c4c3 MK |
1675 | out: |
1676 | spin_unlock(ptl); | |
1677 | out_unlocked: | |
1678 | return ret; | |
1679 | } | |
1680 | ||
953c66c2 AK |
1681 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1682 | { | |
1683 | pgtable_t pgtable; | |
1684 | ||
1685 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1686 | pte_free(mm, pgtable); | |
c4812909 | 1687 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1688 | } |
1689 | ||
71e3aac0 | 1690 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1691 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1692 | { |
da146769 | 1693 | pmd_t orig_pmd; |
bf929152 | 1694 | spinlock_t *ptl; |
71e3aac0 | 1695 | |
ed6a7935 | 1696 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1697 | |
b6ec57f4 KS |
1698 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1699 | if (!ptl) | |
da146769 KS |
1700 | return 0; |
1701 | /* | |
1702 | * For architectures like ppc64 we look at deposited pgtable | |
1703 | * when calling pmdp_huge_get_and_clear. So do the | |
1704 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1705 | * operations. | |
1706 | */ | |
93a98695 AK |
1707 | orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, |
1708 | tlb->fullmm); | |
e5136e87 | 1709 | arch_check_zapped_pmd(vma, orig_pmd); |
da146769 | 1710 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
2484ca9b | 1711 | if (vma_is_special_huge(vma)) { |
3b6521f5 OH |
1712 | if (arch_needs_pgtable_deposit()) |
1713 | zap_deposited_table(tlb->mm, pmd); | |
da146769 | 1714 | spin_unlock(ptl); |
da146769 | 1715 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1716 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1717 | spin_unlock(ptl); |
da146769 | 1718 | } else { |
616b8371 ZY |
1719 | struct page *page = NULL; |
1720 | int flush_needed = 1; | |
1721 | ||
1722 | if (pmd_present(orig_pmd)) { | |
1723 | page = pmd_page(orig_pmd); | |
cea86fe2 | 1724 | page_remove_rmap(page, vma, true); |
616b8371 ZY |
1725 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); |
1726 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1727 | } else if (thp_migration_supported()) { | |
1728 | swp_entry_t entry; | |
1729 | ||
1730 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1731 | entry = pmd_to_swp_entry(orig_pmd); | |
af5cdaf8 | 1732 | page = pfn_swap_entry_to_page(entry); |
616b8371 ZY |
1733 | flush_needed = 0; |
1734 | } else | |
1735 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1736 | ||
b5072380 | 1737 | if (PageAnon(page)) { |
c14a6eb4 | 1738 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1739 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1740 | } else { | |
953c66c2 AK |
1741 | if (arch_needs_pgtable_deposit()) |
1742 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1743 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1744 | } |
616b8371 | 1745 | |
da146769 | 1746 | spin_unlock(ptl); |
616b8371 ZY |
1747 | if (flush_needed) |
1748 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1749 | } |
da146769 | 1750 | return 1; |
71e3aac0 AA |
1751 | } |
1752 | ||
1dd38b6c AK |
1753 | #ifndef pmd_move_must_withdraw |
1754 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1755 | spinlock_t *old_pmd_ptl, | |
1756 | struct vm_area_struct *vma) | |
1757 | { | |
1758 | /* | |
1759 | * With split pmd lock we also need to move preallocated | |
1760 | * PTE page table if new_pmd is on different PMD page table. | |
1761 | * | |
1762 | * We also don't deposit and withdraw tables for file pages. | |
1763 | */ | |
1764 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1765 | } | |
1766 | #endif | |
1767 | ||
ab6e3d09 NH |
1768 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1769 | { | |
1770 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1771 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1772 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1773 | else if (pmd_present(pmd)) | |
1774 | pmd = pmd_mksoft_dirty(pmd); | |
1775 | #endif | |
1776 | return pmd; | |
1777 | } | |
1778 | ||
bf8616d5 | 1779 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
b8aa9d9d | 1780 | unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1781 | { |
bf929152 | 1782 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1783 | pmd_t pmd; |
37a1c49a | 1784 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1785 | bool force_flush = false; |
37a1c49a | 1786 | |
37a1c49a AA |
1787 | /* |
1788 | * The destination pmd shouldn't be established, free_pgtables() | |
a5be621e HD |
1789 | * should have released it; but move_page_tables() might have already |
1790 | * inserted a page table, if racing against shmem/file collapse. | |
37a1c49a | 1791 | */ |
a5be621e | 1792 | if (!pmd_none(*new_pmd)) { |
37a1c49a | 1793 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); |
4b471e88 | 1794 | return false; |
37a1c49a AA |
1795 | } |
1796 | ||
bf929152 KS |
1797 | /* |
1798 | * We don't have to worry about the ordering of src and dst | |
c1e8d7c6 | 1799 | * ptlocks because exclusive mmap_lock prevents deadlock. |
bf929152 | 1800 | */ |
b6ec57f4 KS |
1801 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1802 | if (old_ptl) { | |
bf929152 KS |
1803 | new_ptl = pmd_lockptr(mm, new_pmd); |
1804 | if (new_ptl != old_ptl) | |
1805 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1806 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1807 | if (pmd_present(pmd)) |
a2ce2666 | 1808 | force_flush = true; |
025c5b24 | 1809 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1810 | |
1dd38b6c | 1811 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1812 | pgtable_t pgtable; |
3592806c KS |
1813 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1814 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1815 | } |
ab6e3d09 NH |
1816 | pmd = move_soft_dirty_pmd(pmd); |
1817 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 | 1818 | if (force_flush) |
7c38f181 | 1819 | flush_pmd_tlb_range(vma, old_addr, old_addr + PMD_SIZE); |
eb66ae03 LT |
1820 | if (new_ptl != old_ptl) |
1821 | spin_unlock(new_ptl); | |
bf929152 | 1822 | spin_unlock(old_ptl); |
4b471e88 | 1823 | return true; |
37a1c49a | 1824 | } |
4b471e88 | 1825 | return false; |
37a1c49a AA |
1826 | } |
1827 | ||
f123d74a MG |
1828 | /* |
1829 | * Returns | |
1830 | * - 0 if PMD could not be locked | |
f0953a1b | 1831 | * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary |
e346e668 | 1832 | * or if prot_numa but THP migration is not supported |
f0953a1b | 1833 | * - HPAGE_PMD_NR if protections changed and TLB flush necessary |
f123d74a | 1834 | */ |
4a18419f NA |
1835 | int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
1836 | pmd_t *pmd, unsigned long addr, pgprot_t newprot, | |
1837 | unsigned long cp_flags) | |
cd7548ab JW |
1838 | { |
1839 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1840 | spinlock_t *ptl; |
c9fe6656 | 1841 | pmd_t oldpmd, entry; |
58705444 | 1842 | bool prot_numa = cp_flags & MM_CP_PROT_NUMA; |
292924b2 PX |
1843 | bool uffd_wp = cp_flags & MM_CP_UFFD_WP; |
1844 | bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; | |
6a56ccbc | 1845 | int ret = 1; |
cd7548ab | 1846 | |
4a18419f NA |
1847 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
1848 | ||
e346e668 YS |
1849 | if (prot_numa && !thp_migration_supported()) |
1850 | return 1; | |
1851 | ||
b6ec57f4 | 1852 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1853 | if (!ptl) |
1854 | return 0; | |
e944fd67 | 1855 | |
84c3fc4e ZY |
1856 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1857 | if (is_swap_pmd(*pmd)) { | |
1858 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
d986ba2b | 1859 | struct folio *folio = page_folio(pfn_swap_entry_to_page(entry)); |
24bf08c4 | 1860 | pmd_t newpmd; |
84c3fc4e ZY |
1861 | |
1862 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
4dd845b5 | 1863 | if (is_writable_migration_entry(entry)) { |
84c3fc4e ZY |
1864 | /* |
1865 | * A protection check is difficult so | |
1866 | * just be safe and disable write | |
1867 | */ | |
d986ba2b | 1868 | if (folio_test_anon(folio)) |
6c287605 DH |
1869 | entry = make_readable_exclusive_migration_entry(swp_offset(entry)); |
1870 | else | |
1871 | entry = make_readable_migration_entry(swp_offset(entry)); | |
84c3fc4e | 1872 | newpmd = swp_entry_to_pmd(entry); |
ab6e3d09 NH |
1873 | if (pmd_swp_soft_dirty(*pmd)) |
1874 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
24bf08c4 DH |
1875 | } else { |
1876 | newpmd = *pmd; | |
84c3fc4e | 1877 | } |
24bf08c4 DH |
1878 | |
1879 | if (uffd_wp) | |
1880 | newpmd = pmd_swp_mkuffd_wp(newpmd); | |
1881 | else if (uffd_wp_resolve) | |
1882 | newpmd = pmd_swp_clear_uffd_wp(newpmd); | |
1883 | if (!pmd_same(*pmd, newpmd)) | |
1884 | set_pmd_at(mm, addr, pmd, newpmd); | |
84c3fc4e ZY |
1885 | goto unlock; |
1886 | } | |
1887 | #endif | |
1888 | ||
a1a3a2fc | 1889 | if (prot_numa) { |
d986ba2b | 1890 | struct folio *folio; |
33024536 | 1891 | bool toptier; |
a1a3a2fc HY |
1892 | /* |
1893 | * Avoid trapping faults against the zero page. The read-only | |
1894 | * data is likely to be read-cached on the local CPU and | |
1895 | * local/remote hits to the zero page are not interesting. | |
1896 | */ | |
1897 | if (is_huge_zero_pmd(*pmd)) | |
1898 | goto unlock; | |
025c5b24 | 1899 | |
a1a3a2fc HY |
1900 | if (pmd_protnone(*pmd)) |
1901 | goto unlock; | |
0a85e51d | 1902 | |
d986ba2b KW |
1903 | folio = page_folio(pmd_page(*pmd)); |
1904 | toptier = node_is_toptier(folio_nid(folio)); | |
a1a3a2fc HY |
1905 | /* |
1906 | * Skip scanning top tier node if normal numa | |
1907 | * balancing is disabled | |
1908 | */ | |
1909 | if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && | |
33024536 | 1910 | toptier) |
a1a3a2fc | 1911 | goto unlock; |
33024536 HY |
1912 | |
1913 | if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && | |
1914 | !toptier) | |
d986ba2b KW |
1915 | folio_xchg_access_time(folio, |
1916 | jiffies_to_msecs(jiffies)); | |
a1a3a2fc | 1917 | } |
ced10803 | 1918 | /* |
3e4e28c5 | 1919 | * In case prot_numa, we are under mmap_read_lock(mm). It's critical |
ced10803 | 1920 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED |
3e4e28c5 | 1921 | * which is also under mmap_read_lock(mm): |
ced10803 KS |
1922 | * |
1923 | * CPU0: CPU1: | |
1924 | * change_huge_pmd(prot_numa=1) | |
1925 | * pmdp_huge_get_and_clear_notify() | |
1926 | * madvise_dontneed() | |
1927 | * zap_pmd_range() | |
1928 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1929 | * // skip the pmd | |
1930 | * set_pmd_at(); | |
1931 | * // pmd is re-established | |
1932 | * | |
1933 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1934 | * which may break userspace. | |
1935 | * | |
4f831457 | 1936 | * pmdp_invalidate_ad() is required to make sure we don't miss |
ced10803 KS |
1937 | * dirty/young flags set by hardware. |
1938 | */ | |
4f831457 | 1939 | oldpmd = pmdp_invalidate_ad(vma, addr, pmd); |
ced10803 | 1940 | |
c9fe6656 | 1941 | entry = pmd_modify(oldpmd, newprot); |
f1eb1bac | 1942 | if (uffd_wp) |
292924b2 | 1943 | entry = pmd_mkuffd_wp(entry); |
f1eb1bac | 1944 | else if (uffd_wp_resolve) |
292924b2 PX |
1945 | /* |
1946 | * Leave the write bit to be handled by PF interrupt | |
1947 | * handler, then things like COW could be properly | |
1948 | * handled. | |
1949 | */ | |
1950 | entry = pmd_clear_uffd_wp(entry); | |
c27f479e DH |
1951 | |
1952 | /* See change_pte_range(). */ | |
1953 | if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && !pmd_write(entry) && | |
1954 | can_change_pmd_writable(vma, addr, entry)) | |
161e393c | 1955 | entry = pmd_mkwrite(entry, vma); |
c27f479e | 1956 | |
0a85e51d KS |
1957 | ret = HPAGE_PMD_NR; |
1958 | set_pmd_at(mm, addr, pmd, entry); | |
4a18419f | 1959 | |
c9fe6656 NA |
1960 | if (huge_pmd_needs_flush(oldpmd, entry)) |
1961 | tlb_flush_pmd_range(tlb, addr, HPAGE_PMD_SIZE); | |
0a85e51d KS |
1962 | unlock: |
1963 | spin_unlock(ptl); | |
025c5b24 NH |
1964 | return ret; |
1965 | } | |
1966 | ||
1967 | /* | |
8f19b0c0 | 1968 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1969 | * |
8f19b0c0 HY |
1970 | * Note that if it returns page table lock pointer, this routine returns without |
1971 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1972 | */ |
b6ec57f4 | 1973 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1974 | { |
b6ec57f4 KS |
1975 | spinlock_t *ptl; |
1976 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1977 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1978 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1979 | return ptl; |
1980 | spin_unlock(ptl); | |
1981 | return NULL; | |
cd7548ab JW |
1982 | } |
1983 | ||
a00cc7d9 | 1984 | /* |
d965e390 | 1985 | * Returns page table lock pointer if a given pud maps a thp, NULL otherwise. |
a00cc7d9 | 1986 | * |
d965e390 ML |
1987 | * Note that if it returns page table lock pointer, this routine returns without |
1988 | * unlocking page table lock. So callers must unlock it. | |
a00cc7d9 MW |
1989 | */ |
1990 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1991 | { | |
1992 | spinlock_t *ptl; | |
1993 | ||
1994 | ptl = pud_lock(vma->vm_mm, pud); | |
1995 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1996 | return ptl; | |
1997 | spin_unlock(ptl); | |
1998 | return NULL; | |
1999 | } | |
2000 | ||
2001 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
2002 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
2003 | pud_t *pud, unsigned long addr) | |
2004 | { | |
a00cc7d9 MW |
2005 | spinlock_t *ptl; |
2006 | ||
2007 | ptl = __pud_trans_huge_lock(pud, vma); | |
2008 | if (!ptl) | |
2009 | return 0; | |
74929079 | 2010 | |
f32928ab | 2011 | pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm); |
a00cc7d9 | 2012 | tlb_remove_pud_tlb_entry(tlb, pud, addr); |
2484ca9b | 2013 | if (vma_is_special_huge(vma)) { |
a00cc7d9 MW |
2014 | spin_unlock(ptl); |
2015 | /* No zero page support yet */ | |
2016 | } else { | |
2017 | /* No support for anonymous PUD pages yet */ | |
2018 | BUG(); | |
2019 | } | |
2020 | return 1; | |
2021 | } | |
2022 | ||
2023 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
2024 | unsigned long haddr) | |
2025 | { | |
2026 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
2027 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2028 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
2029 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
2030 | ||
ce9311cf | 2031 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 | 2032 | |
ec8832d0 | 2033 | pudp_huge_clear_flush(vma, haddr, pud); |
a00cc7d9 MW |
2034 | } |
2035 | ||
2036 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
2037 | unsigned long address) | |
2038 | { | |
2039 | spinlock_t *ptl; | |
ac46d4f3 | 2040 | struct mmu_notifier_range range; |
a00cc7d9 | 2041 | |
7d4a8be0 | 2042 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, |
6f4f13e8 | 2043 | address & HPAGE_PUD_MASK, |
ac46d4f3 JG |
2044 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); |
2045 | mmu_notifier_invalidate_range_start(&range); | |
2046 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
2047 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
2048 | goto out; | |
ac46d4f3 | 2049 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
2050 | |
2051 | out: | |
2052 | spin_unlock(ptl); | |
ec8832d0 | 2053 | mmu_notifier_invalidate_range_end(&range); |
a00cc7d9 MW |
2054 | } |
2055 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
2056 | ||
eef1b3ba KS |
2057 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2058 | unsigned long haddr, pmd_t *pmd) | |
2059 | { | |
2060 | struct mm_struct *mm = vma->vm_mm; | |
2061 | pgtable_t pgtable; | |
42b2af2c | 2062 | pmd_t _pmd, old_pmd; |
c9c1ee20 HD |
2063 | unsigned long addr; |
2064 | pte_t *pte; | |
eef1b3ba KS |
2065 | int i; |
2066 | ||
0f10851e JG |
2067 | /* |
2068 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2069 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2070 | * replacing a zero pmd write protected page with a zero pte write | |
2071 | * protected page. | |
2072 | * | |
ee65728e | 2073 | * See Documentation/mm/mmu_notifier.rst |
0f10851e | 2074 | */ |
42b2af2c | 2075 | old_pmd = pmdp_huge_clear_flush(vma, haddr, pmd); |
eef1b3ba KS |
2076 | |
2077 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2078 | pmd_populate(mm, &_pmd, pgtable); | |
2079 | ||
c9c1ee20 HD |
2080 | pte = pte_offset_map(&_pmd, haddr); |
2081 | VM_BUG_ON(!pte); | |
2082 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { | |
2083 | pte_t entry; | |
2084 | ||
2085 | entry = pfn_pte(my_zero_pfn(addr), vma->vm_page_prot); | |
eef1b3ba | 2086 | entry = pte_mkspecial(entry); |
42b2af2c DH |
2087 | if (pmd_uffd_wp(old_pmd)) |
2088 | entry = pte_mkuffd_wp(entry); | |
c33c7948 | 2089 | VM_BUG_ON(!pte_none(ptep_get(pte))); |
c9c1ee20 HD |
2090 | set_pte_at(mm, addr, pte, entry); |
2091 | pte++; | |
eef1b3ba | 2092 | } |
c9c1ee20 | 2093 | pte_unmap(pte - 1); |
eef1b3ba KS |
2094 | smp_wmb(); /* make pte visible before pmd */ |
2095 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2096 | } |
2097 | ||
2098 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2099 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2100 | { |
2101 | struct mm_struct *mm = vma->vm_mm; | |
2102 | struct page *page; | |
2103 | pgtable_t pgtable; | |
423ac9af | 2104 | pmd_t old_pmd, _pmd; |
292924b2 | 2105 | bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; |
0ccf7f16 | 2106 | bool anon_exclusive = false, dirty = false; |
2ac015e2 | 2107 | unsigned long addr; |
c9c1ee20 | 2108 | pte_t *pte; |
eef1b3ba KS |
2109 | int i; |
2110 | ||
2111 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2112 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2113 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2114 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2115 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2116 | |
2117 | count_vm_event(THP_SPLIT_PMD); | |
2118 | ||
d21b9e57 | 2119 | if (!vma_is_anonymous(vma)) { |
ec8832d0 | 2120 | old_pmd = pmdp_huge_clear_flush(vma, haddr, pmd); |
953c66c2 AK |
2121 | /* |
2122 | * We are going to unmap this huge page. So | |
2123 | * just go ahead and zap it | |
2124 | */ | |
2125 | if (arch_needs_pgtable_deposit()) | |
2126 | zap_deposited_table(mm, pmd); | |
2484ca9b | 2127 | if (vma_is_special_huge(vma)) |
d21b9e57 | 2128 | return; |
99fa8a48 HD |
2129 | if (unlikely(is_pmd_migration_entry(old_pmd))) { |
2130 | swp_entry_t entry; | |
2131 | ||
2132 | entry = pmd_to_swp_entry(old_pmd); | |
af5cdaf8 | 2133 | page = pfn_swap_entry_to_page(entry); |
99fa8a48 HD |
2134 | } else { |
2135 | page = pmd_page(old_pmd); | |
2136 | if (!PageDirty(page) && pmd_dirty(old_pmd)) | |
2137 | set_page_dirty(page); | |
2138 | if (!PageReferenced(page) && pmd_young(old_pmd)) | |
2139 | SetPageReferenced(page); | |
cea86fe2 | 2140 | page_remove_rmap(page, vma, true); |
99fa8a48 HD |
2141 | put_page(page); |
2142 | } | |
fadae295 | 2143 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba | 2144 | return; |
99fa8a48 HD |
2145 | } |
2146 | ||
3b77e8c8 | 2147 | if (is_huge_zero_pmd(*pmd)) { |
4645b9fe JG |
2148 | /* |
2149 | * FIXME: Do we want to invalidate secondary mmu by calling | |
1af5a810 AP |
2150 | * mmu_notifier_arch_invalidate_secondary_tlbs() see comments below |
2151 | * inside __split_huge_pmd() ? | |
4645b9fe JG |
2152 | * |
2153 | * We are going from a zero huge page write protected to zero | |
2154 | * small page also write protected so it does not seems useful | |
2155 | * to invalidate secondary mmu at this time. | |
2156 | */ | |
eef1b3ba KS |
2157 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2158 | } | |
2159 | ||
423ac9af AK |
2160 | /* |
2161 | * Up to this point the pmd is present and huge and userland has the | |
2162 | * whole access to the hugepage during the split (which happens in | |
2163 | * place). If we overwrite the pmd with the not-huge version pointing | |
2164 | * to the pte here (which of course we could if all CPUs were bug | |
2165 | * free), userland could trigger a small page size TLB miss on the | |
2166 | * small sized TLB while the hugepage TLB entry is still established in | |
2167 | * the huge TLB. Some CPU doesn't like that. | |
42742d9b AK |
2168 | * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum |
2169 | * 383 on page 105. Intel should be safe but is also warns that it's | |
423ac9af AK |
2170 | * only safe if the permission and cache attributes of the two entries |
2171 | * loaded in the two TLB is identical (which should be the case here). | |
2172 | * But it is generally safer to never allow small and huge TLB entries | |
2173 | * for the same virtual address to be loaded simultaneously. So instead | |
2174 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2175 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2176 | * must remain set at all times on the pmd until the split is complete | |
2177 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2178 | * non-huge version of the pmd entry with pmd_populate. | |
2179 | */ | |
2180 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2181 | ||
423ac9af | 2182 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2183 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2184 | swp_entry_t entry; |
2185 | ||
423ac9af | 2186 | entry = pmd_to_swp_entry(old_pmd); |
af5cdaf8 | 2187 | page = pfn_swap_entry_to_page(entry); |
4dd845b5 | 2188 | write = is_writable_migration_entry(entry); |
6c287605 DH |
2189 | if (PageAnon(page)) |
2190 | anon_exclusive = is_readable_exclusive_migration_entry(entry); | |
2e346877 PX |
2191 | young = is_migration_entry_young(entry); |
2192 | dirty = is_migration_entry_dirty(entry); | |
2e83ee1d | 2193 | soft_dirty = pmd_swp_soft_dirty(old_pmd); |
f45ec5ff | 2194 | uffd_wp = pmd_swp_uffd_wp(old_pmd); |
2e83ee1d | 2195 | } else { |
423ac9af | 2196 | page = pmd_page(old_pmd); |
0ccf7f16 PX |
2197 | if (pmd_dirty(old_pmd)) { |
2198 | dirty = true; | |
2e83ee1d | 2199 | SetPageDirty(page); |
0ccf7f16 | 2200 | } |
2e83ee1d PX |
2201 | write = pmd_write(old_pmd); |
2202 | young = pmd_young(old_pmd); | |
2203 | soft_dirty = pmd_soft_dirty(old_pmd); | |
292924b2 | 2204 | uffd_wp = pmd_uffd_wp(old_pmd); |
6c287605 | 2205 | |
9d84604b | 2206 | VM_BUG_ON_PAGE(!page_count(page), page); |
6c287605 DH |
2207 | |
2208 | /* | |
2209 | * Without "freeze", we'll simply split the PMD, propagating the | |
2210 | * PageAnonExclusive() flag for each PTE by setting it for | |
2211 | * each subpage -- no need to (temporarily) clear. | |
2212 | * | |
2213 | * With "freeze" we want to replace mapped pages by | |
2214 | * migration entries right away. This is only possible if we | |
2215 | * managed to clear PageAnonExclusive() -- see | |
2216 | * set_pmd_migration_entry(). | |
2217 | * | |
2218 | * In case we cannot clear PageAnonExclusive(), split the PMD | |
2219 | * only and let try_to_migrate_one() fail later. | |
088b8aa5 DH |
2220 | * |
2221 | * See page_try_share_anon_rmap(): invalidate PMD first. | |
6c287605 DH |
2222 | */ |
2223 | anon_exclusive = PageAnon(page) && PageAnonExclusive(page); | |
2224 | if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) | |
2225 | freeze = false; | |
96d82deb HD |
2226 | if (!freeze) |
2227 | page_ref_add(page, HPAGE_PMD_NR - 1); | |
2e83ee1d | 2228 | } |
eef1b3ba | 2229 | |
423ac9af AK |
2230 | /* |
2231 | * Withdraw the table only after we mark the pmd entry invalid. | |
2232 | * This's critical for some architectures (Power). | |
2233 | */ | |
eef1b3ba KS |
2234 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2235 | pmd_populate(mm, &_pmd, pgtable); | |
2236 | ||
c9c1ee20 HD |
2237 | pte = pte_offset_map(&_pmd, haddr); |
2238 | VM_BUG_ON(!pte); | |
2ac015e2 | 2239 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
c9c1ee20 | 2240 | pte_t entry; |
eef1b3ba KS |
2241 | /* |
2242 | * Note that NUMA hinting access restrictions are not | |
2243 | * transferred to avoid any possibility of altering | |
2244 | * permissions across VMAs. | |
2245 | */ | |
84c3fc4e | 2246 | if (freeze || pmd_migration) { |
ba988280 | 2247 | swp_entry_t swp_entry; |
4dd845b5 AP |
2248 | if (write) |
2249 | swp_entry = make_writable_migration_entry( | |
2250 | page_to_pfn(page + i)); | |
6c287605 DH |
2251 | else if (anon_exclusive) |
2252 | swp_entry = make_readable_exclusive_migration_entry( | |
2253 | page_to_pfn(page + i)); | |
4dd845b5 AP |
2254 | else |
2255 | swp_entry = make_readable_migration_entry( | |
2256 | page_to_pfn(page + i)); | |
2e346877 PX |
2257 | if (young) |
2258 | swp_entry = make_migration_entry_young(swp_entry); | |
2259 | if (dirty) | |
2260 | swp_entry = make_migration_entry_dirty(swp_entry); | |
ba988280 | 2261 | entry = swp_entry_to_pte(swp_entry); |
804dd150 AA |
2262 | if (soft_dirty) |
2263 | entry = pte_swp_mksoft_dirty(entry); | |
f45ec5ff PX |
2264 | if (uffd_wp) |
2265 | entry = pte_swp_mkuffd_wp(entry); | |
ba988280 | 2266 | } else { |
6d2329f8 | 2267 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
1462c52e | 2268 | if (write) |
161e393c | 2269 | entry = pte_mkwrite(entry, vma); |
6c287605 DH |
2270 | if (anon_exclusive) |
2271 | SetPageAnonExclusive(page + i); | |
ba988280 KS |
2272 | if (!young) |
2273 | entry = pte_mkold(entry); | |
e833bc50 PX |
2274 | /* NOTE: this may set soft-dirty too on some archs */ |
2275 | if (dirty) | |
2276 | entry = pte_mkdirty(entry); | |
804dd150 AA |
2277 | if (soft_dirty) |
2278 | entry = pte_mksoft_dirty(entry); | |
292924b2 PX |
2279 | if (uffd_wp) |
2280 | entry = pte_mkuffd_wp(entry); | |
5ba72b4d | 2281 | page_add_anon_rmap(page + i, vma, addr, RMAP_NONE); |
ba988280 | 2282 | } |
c33c7948 | 2283 | VM_BUG_ON(!pte_none(ptep_get(pte))); |
2ac015e2 | 2284 | set_pte_at(mm, addr, pte, entry); |
c9c1ee20 | 2285 | pte++; |
eef1b3ba | 2286 | } |
c9c1ee20 | 2287 | pte_unmap(pte - 1); |
eef1b3ba | 2288 | |
cb67f428 HD |
2289 | if (!pmd_migration) |
2290 | page_remove_rmap(page, vma, true); | |
96d82deb HD |
2291 | if (freeze) |
2292 | put_page(page); | |
eef1b3ba KS |
2293 | |
2294 | smp_wmb(); /* make pte visible before pmd */ | |
2295 | pmd_populate(mm, pmd, pgtable); | |
2296 | } | |
2297 | ||
2298 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
af28a988 | 2299 | unsigned long address, bool freeze, struct folio *folio) |
eef1b3ba KS |
2300 | { |
2301 | spinlock_t *ptl; | |
ac46d4f3 | 2302 | struct mmu_notifier_range range; |
eef1b3ba | 2303 | |
7d4a8be0 | 2304 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, |
6f4f13e8 | 2305 | address & HPAGE_PMD_MASK, |
ac46d4f3 JG |
2306 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); |
2307 | mmu_notifier_invalidate_range_start(&range); | |
2308 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2309 | |
2310 | /* | |
af28a988 MWO |
2311 | * If caller asks to setup a migration entry, we need a folio to check |
2312 | * pmd against. Otherwise we can end up replacing wrong folio. | |
33f4751e | 2313 | */ |
af28a988 | 2314 | VM_BUG_ON(freeze && !folio); |
83a8441f | 2315 | VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); |
33f4751e | 2316 | |
7f760917 | 2317 | if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || |
83a8441f | 2318 | is_pmd_migration_entry(*pmd)) { |
cea33328 ML |
2319 | /* |
2320 | * It's safe to call pmd_page when folio is set because it's | |
2321 | * guaranteed that pmd is present. | |
2322 | */ | |
83a8441f MWO |
2323 | if (folio && folio != page_folio(pmd_page(*pmd))) |
2324 | goto out; | |
7f760917 | 2325 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
83a8441f | 2326 | } |
7f760917 | 2327 | |
e90309c9 | 2328 | out: |
eef1b3ba | 2329 | spin_unlock(ptl); |
ec8832d0 | 2330 | mmu_notifier_invalidate_range_end(&range); |
eef1b3ba KS |
2331 | } |
2332 | ||
fec89c10 | 2333 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
af28a988 | 2334 | bool freeze, struct folio *folio) |
94fcc585 | 2335 | { |
50722804 | 2336 | pmd_t *pmd = mm_find_pmd(vma->vm_mm, address); |
94fcc585 | 2337 | |
50722804 | 2338 | if (!pmd) |
f72e7dcd HD |
2339 | return; |
2340 | ||
af28a988 | 2341 | __split_huge_pmd(vma, pmd, address, freeze, folio); |
94fcc585 AA |
2342 | } |
2343 | ||
71f9e58e ML |
2344 | static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) |
2345 | { | |
2346 | /* | |
2347 | * If the new address isn't hpage aligned and it could previously | |
2348 | * contain an hugepage: check if we need to split an huge pmd. | |
2349 | */ | |
2350 | if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && | |
2351 | range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), | |
2352 | ALIGN(address, HPAGE_PMD_SIZE))) | |
2353 | split_huge_pmd_address(vma, address, false, NULL); | |
2354 | } | |
2355 | ||
e1b9996b | 2356 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2357 | unsigned long start, |
2358 | unsigned long end, | |
2359 | long adjust_next) | |
2360 | { | |
71f9e58e ML |
2361 | /* Check if we need to split start first. */ |
2362 | split_huge_pmd_if_needed(vma, start); | |
94fcc585 | 2363 | |
71f9e58e ML |
2364 | /* Check if we need to split end next. */ |
2365 | split_huge_pmd_if_needed(vma, end); | |
94fcc585 AA |
2366 | |
2367 | /* | |
68540502 | 2368 | * If we're also updating the next vma vm_start, |
71f9e58e | 2369 | * check if we need to split it. |
94fcc585 AA |
2370 | */ |
2371 | if (adjust_next > 0) { | |
68540502 | 2372 | struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end); |
94fcc585 | 2373 | unsigned long nstart = next->vm_start; |
f9d86a60 | 2374 | nstart += adjust_next; |
71f9e58e | 2375 | split_huge_pmd_if_needed(next, nstart); |
94fcc585 AA |
2376 | } |
2377 | } | |
e9b61f19 | 2378 | |
684555aa | 2379 | static void unmap_folio(struct folio *folio) |
e9b61f19 | 2380 | { |
a98a2f0c AP |
2381 | enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | |
2382 | TTU_SYNC; | |
e9b61f19 | 2383 | |
684555aa | 2384 | VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); |
e9b61f19 | 2385 | |
a98a2f0c AP |
2386 | /* |
2387 | * Anon pages need migration entries to preserve them, but file | |
2388 | * pages can simply be left unmapped, then faulted back on demand. | |
2389 | * If that is ever changed (perhaps for mlock), update remap_page(). | |
2390 | */ | |
4b8554c5 MWO |
2391 | if (folio_test_anon(folio)) |
2392 | try_to_migrate(folio, ttu_flags); | |
a98a2f0c | 2393 | else |
869f7ee6 | 2394 | try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); |
e9b61f19 KS |
2395 | } |
2396 | ||
4eecb8b9 | 2397 | static void remap_page(struct folio *folio, unsigned long nr) |
e9b61f19 | 2398 | { |
4eecb8b9 | 2399 | int i = 0; |
ab02c252 | 2400 | |
684555aa | 2401 | /* If unmap_folio() uses try_to_migrate() on file, remove this check */ |
4eecb8b9 | 2402 | if (!folio_test_anon(folio)) |
ab02c252 | 2403 | return; |
4eecb8b9 MWO |
2404 | for (;;) { |
2405 | remove_migration_ptes(folio, folio, true); | |
2406 | i += folio_nr_pages(folio); | |
2407 | if (i >= nr) | |
2408 | break; | |
2409 | folio = folio_next(folio); | |
ace71a19 | 2410 | } |
e9b61f19 KS |
2411 | } |
2412 | ||
94866635 | 2413 | static void lru_add_page_tail(struct page *head, struct page *tail, |
88dcb9a3 AS |
2414 | struct lruvec *lruvec, struct list_head *list) |
2415 | { | |
94866635 AS |
2416 | VM_BUG_ON_PAGE(!PageHead(head), head); |
2417 | VM_BUG_ON_PAGE(PageCompound(tail), head); | |
2418 | VM_BUG_ON_PAGE(PageLRU(tail), head); | |
6168d0da | 2419 | lockdep_assert_held(&lruvec->lru_lock); |
88dcb9a3 | 2420 | |
6dbb5741 | 2421 | if (list) { |
88dcb9a3 | 2422 | /* page reclaim is reclaiming a huge page */ |
6dbb5741 | 2423 | VM_WARN_ON(PageLRU(head)); |
94866635 AS |
2424 | get_page(tail); |
2425 | list_add_tail(&tail->lru, list); | |
88dcb9a3 | 2426 | } else { |
6dbb5741 AS |
2427 | /* head is still on lru (and we have it frozen) */ |
2428 | VM_WARN_ON(!PageLRU(head)); | |
07ca7606 HD |
2429 | if (PageUnevictable(tail)) |
2430 | tail->mlock_count = 0; | |
2431 | else | |
2432 | list_add_tail(&tail->lru, &head->lru); | |
6dbb5741 | 2433 | SetPageLRU(tail); |
88dcb9a3 AS |
2434 | } |
2435 | } | |
2436 | ||
07e09c48 | 2437 | static void __split_huge_page_tail(struct folio *folio, int tail, |
e9b61f19 KS |
2438 | struct lruvec *lruvec, struct list_head *list) |
2439 | { | |
07e09c48 | 2440 | struct page *head = &folio->page; |
e9b61f19 | 2441 | struct page *page_tail = head + tail; |
07e09c48 DH |
2442 | /* |
2443 | * Careful: new_folio is not a "real" folio before we cleared PageTail. | |
2444 | * Don't pass it around before clear_compound_head(). | |
2445 | */ | |
2446 | struct folio *new_folio = (struct folio *)page_tail; | |
e9b61f19 | 2447 | |
8df651c7 | 2448 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2449 | |
2450 | /* | |
605ca5ed KK |
2451 | * Clone page flags before unfreezing refcount. |
2452 | * | |
2453 | * After successful get_page_unless_zero() might follow flags change, | |
8958b249 | 2454 | * for example lock_page() which set PG_waiters. |
6c287605 DH |
2455 | * |
2456 | * Note that for mapped sub-pages of an anonymous THP, | |
684555aa | 2457 | * PG_anon_exclusive has been cleared in unmap_folio() and is stored in |
6c287605 DH |
2458 | * the migration entry instead from where remap_page() will restore it. |
2459 | * We can still have PG_anon_exclusive set on effectively unmapped and | |
2460 | * unreferenced sub-pages of an anonymous THP: we can simply drop | |
2461 | * PG_anon_exclusive (-> PG_mappedtodisk) for these here. | |
e9b61f19 | 2462 | */ |
e9b61f19 KS |
2463 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2464 | page_tail->flags |= (head->flags & | |
2465 | ((1L << PG_referenced) | | |
2466 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2467 | (1L << PG_swapcache) | |
e9b61f19 KS |
2468 | (1L << PG_mlocked) | |
2469 | (1L << PG_uptodate) | | |
2470 | (1L << PG_active) | | |
1899ad18 | 2471 | (1L << PG_workingset) | |
e9b61f19 | 2472 | (1L << PG_locked) | |
b8d3c4c3 | 2473 | (1L << PG_unevictable) | |
b0284cd2 | 2474 | #ifdef CONFIG_ARCH_USES_PG_ARCH_X |
72e6afa0 | 2475 | (1L << PG_arch_2) | |
ef6458b1 | 2476 | (1L << PG_arch_3) | |
72e6afa0 | 2477 | #endif |
ec1c86b2 YZ |
2478 | (1L << PG_dirty) | |
2479 | LRU_GEN_MASK | LRU_REFS_MASK)); | |
e9b61f19 | 2480 | |
cb67f428 | 2481 | /* ->mapping in first and second tail page is replaced by other uses */ |
173d9d9f HD |
2482 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, |
2483 | page_tail); | |
2484 | page_tail->mapping = head->mapping; | |
2485 | page_tail->index = head->index + tail; | |
71e2d666 MG |
2486 | |
2487 | /* | |
cfeed8ff DH |
2488 | * page->private should not be set in tail pages. Fix up and warn once |
2489 | * if private is unexpectedly set. | |
71e2d666 | 2490 | */ |
cfeed8ff DH |
2491 | if (unlikely(page_tail->private)) { |
2492 | VM_WARN_ON_ONCE_PAGE(true, page_tail); | |
71e2d666 MG |
2493 | page_tail->private = 0; |
2494 | } | |
07e09c48 DH |
2495 | if (folio_test_swapcache(folio)) |
2496 | new_folio->swap.val = folio->swap.val + tail; | |
173d9d9f | 2497 | |
605ca5ed | 2498 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2499 | smp_wmb(); |
2500 | ||
605ca5ed KK |
2501 | /* |
2502 | * Clear PageTail before unfreezing page refcount. | |
2503 | * | |
2504 | * After successful get_page_unless_zero() might follow put_page() | |
2505 | * which needs correct compound_head(). | |
2506 | */ | |
e9b61f19 KS |
2507 | clear_compound_head(page_tail); |
2508 | ||
605ca5ed KK |
2509 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2510 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2511 | PageSwapCache(head))); | |
2512 | ||
e9b61f19 KS |
2513 | if (page_is_young(head)) |
2514 | set_page_young(page_tail); | |
2515 | if (page_is_idle(head)) | |
2516 | set_page_idle(page_tail); | |
2517 | ||
c8253011 | 2518 | folio_xchg_last_cpupid(new_folio, folio_last_cpupid(folio)); |
94723aaf MH |
2519 | |
2520 | /* | |
2521 | * always add to the tail because some iterators expect new | |
2522 | * pages to show after the currently processed elements - e.g. | |
2523 | * migrate_pages | |
2524 | */ | |
e9b61f19 | 2525 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2526 | } |
2527 | ||
baa355fd | 2528 | static void __split_huge_page(struct page *page, struct list_head *list, |
b6769834 | 2529 | pgoff_t end) |
e9b61f19 | 2530 | { |
e809c3fe MWO |
2531 | struct folio *folio = page_folio(page); |
2532 | struct page *head = &folio->page; | |
e9b61f19 | 2533 | struct lruvec *lruvec; |
4101196b MWO |
2534 | struct address_space *swap_cache = NULL; |
2535 | unsigned long offset = 0; | |
8cce5475 | 2536 | unsigned int nr = thp_nr_pages(head); |
509f0069 | 2537 | int i, nr_dropped = 0; |
e9b61f19 | 2538 | |
e9b61f19 | 2539 | /* complete memcg works before add pages to LRU */ |
be6c8982 | 2540 | split_page_memcg(head, nr); |
e9b61f19 | 2541 | |
07e09c48 DH |
2542 | if (folio_test_anon(folio) && folio_test_swapcache(folio)) { |
2543 | offset = swp_offset(folio->swap); | |
2544 | swap_cache = swap_address_space(folio->swap); | |
4101196b MWO |
2545 | xa_lock(&swap_cache->i_pages); |
2546 | } | |
2547 | ||
f0953a1b | 2548 | /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ |
e809c3fe | 2549 | lruvec = folio_lruvec_lock(folio); |
b6769834 | 2550 | |
eac96c3e YS |
2551 | ClearPageHasHWPoisoned(head); |
2552 | ||
8cce5475 | 2553 | for (i = nr - 1; i >= 1; i--) { |
07e09c48 | 2554 | __split_huge_page_tail(folio, i, lruvec, list); |
d144bf62 | 2555 | /* Some pages can be beyond EOF: drop them from page cache */ |
baa355fd | 2556 | if (head[i].index >= end) { |
fb5c2029 MWO |
2557 | struct folio *tail = page_folio(head + i); |
2558 | ||
d144bf62 | 2559 | if (shmem_mapping(head->mapping)) |
509f0069 | 2560 | nr_dropped++; |
fb5c2029 MWO |
2561 | else if (folio_test_clear_dirty(tail)) |
2562 | folio_account_cleaned(tail, | |
2563 | inode_to_wb(folio->mapping->host)); | |
2564 | __filemap_remove_folio(tail, NULL); | |
2565 | folio_put(tail); | |
4101196b MWO |
2566 | } else if (!PageAnon(page)) { |
2567 | __xa_store(&head->mapping->i_pages, head[i].index, | |
2568 | head + i, 0); | |
2569 | } else if (swap_cache) { | |
2570 | __xa_store(&swap_cache->i_pages, offset + i, | |
2571 | head + i, 0); | |
baa355fd KS |
2572 | } |
2573 | } | |
e9b61f19 KS |
2574 | |
2575 | ClearPageCompound(head); | |
6168d0da | 2576 | unlock_page_lruvec(lruvec); |
b6769834 | 2577 | /* Caller disabled irqs, so they are still disabled here */ |
f7da677b | 2578 | |
8cce5475 | 2579 | split_page_owner(head, nr); |
f7da677b | 2580 | |
baa355fd KS |
2581 | /* See comment in __split_huge_page_tail() */ |
2582 | if (PageAnon(head)) { | |
aa5dc07f | 2583 | /* Additional pin to swap cache */ |
4101196b | 2584 | if (PageSwapCache(head)) { |
38d8b4e6 | 2585 | page_ref_add(head, 2); |
4101196b MWO |
2586 | xa_unlock(&swap_cache->i_pages); |
2587 | } else { | |
38d8b4e6 | 2588 | page_ref_inc(head); |
4101196b | 2589 | } |
baa355fd | 2590 | } else { |
aa5dc07f | 2591 | /* Additional pin to page cache */ |
baa355fd | 2592 | page_ref_add(head, 2); |
b93b0163 | 2593 | xa_unlock(&head->mapping->i_pages); |
baa355fd | 2594 | } |
b6769834 | 2595 | local_irq_enable(); |
e9b61f19 | 2596 | |
509f0069 HD |
2597 | if (nr_dropped) |
2598 | shmem_uncharge(head->mapping->host, nr_dropped); | |
4eecb8b9 | 2599 | remap_page(folio, nr); |
e9b61f19 | 2600 | |
07e09c48 DH |
2601 | if (folio_test_swapcache(folio)) |
2602 | split_swap_cluster(folio->swap); | |
c4f9c701 | 2603 | |
8cce5475 | 2604 | for (i = 0; i < nr; i++) { |
e9b61f19 KS |
2605 | struct page *subpage = head + i; |
2606 | if (subpage == page) | |
2607 | continue; | |
2608 | unlock_page(subpage); | |
2609 | ||
2610 | /* | |
2611 | * Subpages may be freed if there wasn't any mapping | |
2612 | * like if add_to_swap() is running on a lru page that | |
2613 | * had its mapping zapped. And freeing these pages | |
2614 | * requires taking the lru_lock so we do the put_page | |
2615 | * of the tail pages after the split is complete. | |
2616 | */ | |
0b175468 | 2617 | free_page_and_swap_cache(subpage); |
e9b61f19 KS |
2618 | } |
2619 | } | |
2620 | ||
b8f593cd | 2621 | /* Racy check whether the huge page can be split */ |
d4b4084a | 2622 | bool can_split_folio(struct folio *folio, int *pextra_pins) |
b8f593cd HY |
2623 | { |
2624 | int extra_pins; | |
2625 | ||
aa5dc07f | 2626 | /* Additional pins from page cache */ |
d4b4084a MWO |
2627 | if (folio_test_anon(folio)) |
2628 | extra_pins = folio_test_swapcache(folio) ? | |
2629 | folio_nr_pages(folio) : 0; | |
b8f593cd | 2630 | else |
d4b4084a | 2631 | extra_pins = folio_nr_pages(folio); |
b8f593cd HY |
2632 | if (pextra_pins) |
2633 | *pextra_pins = extra_pins; | |
d4b4084a | 2634 | return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; |
b8f593cd HY |
2635 | } |
2636 | ||
e9b61f19 KS |
2637 | /* |
2638 | * This function splits huge page into normal pages. @page can point to any | |
2639 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2640 | * | |
2641 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2642 | * The huge page must be locked. | |
2643 | * | |
2644 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2645 | * | |
2646 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2647 | * the hugepage. | |
2648 | * | |
2649 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2650 | * they are not mapped. | |
2651 | * | |
2652 | * Returns 0 if the hugepage is split successfully. | |
2653 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2654 | * us. | |
2655 | */ | |
2656 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2657 | { | |
4eecb8b9 | 2658 | struct folio *folio = page_folio(page); |
f8baa6be | 2659 | struct deferred_split *ds_queue = get_deferred_split_queue(folio); |
3e9a13da | 2660 | XA_STATE(xas, &folio->mapping->i_pages, folio->index); |
baa355fd KS |
2661 | struct anon_vma *anon_vma = NULL; |
2662 | struct address_space *mapping = NULL; | |
504e070d | 2663 | int extra_pins, ret; |
006d3ff2 | 2664 | pgoff_t end; |
478d134e | 2665 | bool is_hzp; |
e9b61f19 | 2666 | |
3e9a13da MWO |
2667 | VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); |
2668 | VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); | |
e9b61f19 | 2669 | |
3e9a13da | 2670 | is_hzp = is_huge_zero_page(&folio->page); |
4737edbb NH |
2671 | if (is_hzp) { |
2672 | pr_warn_ratelimited("Called split_huge_page for huge zero page\n"); | |
478d134e | 2673 | return -EBUSY; |
4737edbb | 2674 | } |
478d134e | 2675 | |
3e9a13da | 2676 | if (folio_test_writeback(folio)) |
59807685 HY |
2677 | return -EBUSY; |
2678 | ||
3e9a13da | 2679 | if (folio_test_anon(folio)) { |
baa355fd | 2680 | /* |
c1e8d7c6 | 2681 | * The caller does not necessarily hold an mmap_lock that would |
baa355fd KS |
2682 | * prevent the anon_vma disappearing so we first we take a |
2683 | * reference to it and then lock the anon_vma for write. This | |
2f031c6f | 2684 | * is similar to folio_lock_anon_vma_read except the write lock |
baa355fd KS |
2685 | * is taken to serialise against parallel split or collapse |
2686 | * operations. | |
2687 | */ | |
29eea9b5 | 2688 | anon_vma = folio_get_anon_vma(folio); |
baa355fd KS |
2689 | if (!anon_vma) { |
2690 | ret = -EBUSY; | |
2691 | goto out; | |
2692 | } | |
006d3ff2 | 2693 | end = -1; |
baa355fd KS |
2694 | mapping = NULL; |
2695 | anon_vma_lock_write(anon_vma); | |
2696 | } else { | |
6a3edd29 YF |
2697 | gfp_t gfp; |
2698 | ||
3e9a13da | 2699 | mapping = folio->mapping; |
baa355fd KS |
2700 | |
2701 | /* Truncated ? */ | |
2702 | if (!mapping) { | |
2703 | ret = -EBUSY; | |
2704 | goto out; | |
2705 | } | |
2706 | ||
6a3edd29 YF |
2707 | gfp = current_gfp_context(mapping_gfp_mask(mapping) & |
2708 | GFP_RECLAIM_MASK); | |
2709 | ||
0201ebf2 | 2710 | if (!filemap_release_folio(folio, gfp)) { |
6a3edd29 YF |
2711 | ret = -EBUSY; |
2712 | goto out; | |
2713 | } | |
2714 | ||
3e9a13da | 2715 | xas_split_alloc(&xas, folio, folio_order(folio), gfp); |
6b24ca4a MWO |
2716 | if (xas_error(&xas)) { |
2717 | ret = xas_error(&xas); | |
2718 | goto out; | |
2719 | } | |
2720 | ||
baa355fd KS |
2721 | anon_vma = NULL; |
2722 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2723 | |
2724 | /* | |
2725 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2726 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2727 | * which cannot be nested inside the page tree lock. So note | |
2728 | * end now: i_size itself may be changed at any moment, but | |
3e9a13da | 2729 | * folio lock is good enough to serialize the trimming. |
006d3ff2 HD |
2730 | */ |
2731 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
d144bf62 HD |
2732 | if (shmem_mapping(mapping)) |
2733 | end = shmem_fallocend(mapping->host, end); | |
e9b61f19 | 2734 | } |
e9b61f19 KS |
2735 | |
2736 | /* | |
684555aa | 2737 | * Racy check if we can split the page, before unmap_folio() will |
e9b61f19 KS |
2738 | * split PMDs |
2739 | */ | |
d4b4084a | 2740 | if (!can_split_folio(folio, &extra_pins)) { |
fd4a7ac3 | 2741 | ret = -EAGAIN; |
e9b61f19 KS |
2742 | goto out_unlock; |
2743 | } | |
2744 | ||
684555aa | 2745 | unmap_folio(folio); |
e9b61f19 | 2746 | |
b6769834 AS |
2747 | /* block interrupt reentry in xa_lock and spinlock */ |
2748 | local_irq_disable(); | |
baa355fd | 2749 | if (mapping) { |
baa355fd | 2750 | /* |
3e9a13da MWO |
2751 | * Check if the folio is present in page cache. |
2752 | * We assume all tail are present too, if folio is there. | |
baa355fd | 2753 | */ |
6b24ca4a MWO |
2754 | xas_lock(&xas); |
2755 | xas_reset(&xas); | |
3e9a13da | 2756 | if (xas_load(&xas) != folio) |
baa355fd KS |
2757 | goto fail; |
2758 | } | |
2759 | ||
0139aa7b | 2760 | /* Prevent deferred_split_scan() touching ->_refcount */ |
364c1eeb | 2761 | spin_lock(&ds_queue->split_queue_lock); |
3e9a13da | 2762 | if (folio_ref_freeze(folio, 1 + extra_pins)) { |
4375a553 | 2763 | if (!list_empty(&folio->_deferred_list)) { |
364c1eeb | 2764 | ds_queue->split_queue_len--; |
4375a553 | 2765 | list_del(&folio->_deferred_list); |
9a982250 | 2766 | } |
afb97172 | 2767 | spin_unlock(&ds_queue->split_queue_lock); |
06d3eff6 | 2768 | if (mapping) { |
3e9a13da | 2769 | int nr = folio_nr_pages(folio); |
bf9ecead | 2770 | |
3e9a13da | 2771 | xas_split(&xas, folio, folio_order(folio)); |
a48d5bdc SR |
2772 | if (folio_test_pmd_mappable(folio)) { |
2773 | if (folio_test_swapbacked(folio)) { | |
2774 | __lruvec_stat_mod_folio(folio, | |
2775 | NR_SHMEM_THPS, -nr); | |
2776 | } else { | |
2777 | __lruvec_stat_mod_folio(folio, | |
2778 | NR_FILE_THPS, -nr); | |
2779 | filemap_nr_thps_dec(mapping); | |
2780 | } | |
1ca7554d | 2781 | } |
06d3eff6 KS |
2782 | } |
2783 | ||
b6769834 | 2784 | __split_huge_page(page, list, end); |
c4f9c701 | 2785 | ret = 0; |
e9b61f19 | 2786 | } else { |
364c1eeb | 2787 | spin_unlock(&ds_queue->split_queue_lock); |
504e070d YS |
2788 | fail: |
2789 | if (mapping) | |
6b24ca4a | 2790 | xas_unlock(&xas); |
b6769834 | 2791 | local_irq_enable(); |
4eecb8b9 | 2792 | remap_page(folio, folio_nr_pages(folio)); |
fd4a7ac3 | 2793 | ret = -EAGAIN; |
e9b61f19 KS |
2794 | } |
2795 | ||
2796 | out_unlock: | |
baa355fd KS |
2797 | if (anon_vma) { |
2798 | anon_vma_unlock_write(anon_vma); | |
2799 | put_anon_vma(anon_vma); | |
2800 | } | |
2801 | if (mapping) | |
2802 | i_mmap_unlock_read(mapping); | |
e9b61f19 | 2803 | out: |
69a37a8b | 2804 | xas_destroy(&xas); |
e9b61f19 KS |
2805 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); |
2806 | return ret; | |
2807 | } | |
9a982250 | 2808 | |
8dc4a8f1 | 2809 | void folio_undo_large_rmappable(struct folio *folio) |
9a982250 | 2810 | { |
8dc4a8f1 | 2811 | struct deferred_split *ds_queue; |
9a982250 KS |
2812 | unsigned long flags; |
2813 | ||
deedad80 YF |
2814 | /* |
2815 | * At this point, there is no one trying to add the folio to | |
2816 | * deferred_list. If folio is not in deferred_list, it's safe | |
2817 | * to check without acquiring the split_queue_lock. | |
2818 | */ | |
8dc4a8f1 MWO |
2819 | if (data_race(list_empty(&folio->_deferred_list))) |
2820 | return; | |
2821 | ||
2822 | ds_queue = get_deferred_split_queue(folio); | |
2823 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); | |
2824 | if (!list_empty(&folio->_deferred_list)) { | |
2825 | ds_queue->split_queue_len--; | |
2826 | list_del(&folio->_deferred_list); | |
9a982250 | 2827 | } |
8dc4a8f1 | 2828 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2829 | } |
2830 | ||
f158ed61 | 2831 | void deferred_split_folio(struct folio *folio) |
9a982250 | 2832 | { |
f8baa6be | 2833 | struct deferred_split *ds_queue = get_deferred_split_queue(folio); |
87eaceb3 | 2834 | #ifdef CONFIG_MEMCG |
8991de90 | 2835 | struct mem_cgroup *memcg = folio_memcg(folio); |
87eaceb3 | 2836 | #endif |
9a982250 KS |
2837 | unsigned long flags; |
2838 | ||
8991de90 | 2839 | VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); |
9a982250 | 2840 | |
87eaceb3 YS |
2841 | /* |
2842 | * The try_to_unmap() in page reclaim path might reach here too, | |
2843 | * this may cause a race condition to corrupt deferred split queue. | |
8991de90 | 2844 | * And, if page reclaim is already handling the same folio, it is |
87eaceb3 YS |
2845 | * unnecessary to handle it again in shrinker. |
2846 | * | |
8991de90 MWO |
2847 | * Check the swapcache flag to determine if the folio is being |
2848 | * handled by page reclaim since THP swap would add the folio into | |
87eaceb3 YS |
2849 | * swap cache before calling try_to_unmap(). |
2850 | */ | |
8991de90 | 2851 | if (folio_test_swapcache(folio)) |
87eaceb3 YS |
2852 | return; |
2853 | ||
8991de90 | 2854 | if (!list_empty(&folio->_deferred_list)) |
87eaceb3 YS |
2855 | return; |
2856 | ||
364c1eeb | 2857 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
8991de90 | 2858 | if (list_empty(&folio->_deferred_list)) { |
f9719a03 | 2859 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
8991de90 | 2860 | list_add_tail(&folio->_deferred_list, &ds_queue->split_queue); |
364c1eeb | 2861 | ds_queue->split_queue_len++; |
87eaceb3 YS |
2862 | #ifdef CONFIG_MEMCG |
2863 | if (memcg) | |
8991de90 | 2864 | set_shrinker_bit(memcg, folio_nid(folio), |
54d91729 | 2865 | deferred_split_shrinker->id); |
87eaceb3 | 2866 | #endif |
9a982250 | 2867 | } |
364c1eeb | 2868 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2869 | } |
2870 | ||
2871 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2872 | struct shrink_control *sc) | |
2873 | { | |
a3d0a918 | 2874 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2875 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
87eaceb3 YS |
2876 | |
2877 | #ifdef CONFIG_MEMCG | |
2878 | if (sc->memcg) | |
2879 | ds_queue = &sc->memcg->deferred_split_queue; | |
2880 | #endif | |
364c1eeb | 2881 | return READ_ONCE(ds_queue->split_queue_len); |
9a982250 KS |
2882 | } |
2883 | ||
2884 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2885 | struct shrink_control *sc) | |
2886 | { | |
a3d0a918 | 2887 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2888 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
9a982250 | 2889 | unsigned long flags; |
4375a553 MWO |
2890 | LIST_HEAD(list); |
2891 | struct folio *folio, *next; | |
9a982250 KS |
2892 | int split = 0; |
2893 | ||
87eaceb3 YS |
2894 | #ifdef CONFIG_MEMCG |
2895 | if (sc->memcg) | |
2896 | ds_queue = &sc->memcg->deferred_split_queue; | |
2897 | #endif | |
2898 | ||
364c1eeb | 2899 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2900 | /* Take pin on all head pages to avoid freeing them under us */ |
4375a553 MWO |
2901 | list_for_each_entry_safe(folio, next, &ds_queue->split_queue, |
2902 | _deferred_list) { | |
2903 | if (folio_try_get(folio)) { | |
2904 | list_move(&folio->_deferred_list, &list); | |
e3ae1953 | 2905 | } else { |
4375a553 MWO |
2906 | /* We lost race with folio_put() */ |
2907 | list_del_init(&folio->_deferred_list); | |
364c1eeb | 2908 | ds_queue->split_queue_len--; |
9a982250 | 2909 | } |
e3ae1953 KS |
2910 | if (!--sc->nr_to_scan) |
2911 | break; | |
9a982250 | 2912 | } |
364c1eeb | 2913 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 | 2914 | |
4375a553 MWO |
2915 | list_for_each_entry_safe(folio, next, &list, _deferred_list) { |
2916 | if (!folio_trylock(folio)) | |
fa41b900 | 2917 | goto next; |
9a982250 | 2918 | /* split_huge_page() removes page from list on success */ |
4375a553 | 2919 | if (!split_folio(folio)) |
9a982250 | 2920 | split++; |
4375a553 | 2921 | folio_unlock(folio); |
fa41b900 | 2922 | next: |
4375a553 | 2923 | folio_put(folio); |
9a982250 KS |
2924 | } |
2925 | ||
364c1eeb YS |
2926 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
2927 | list_splice_tail(&list, &ds_queue->split_queue); | |
2928 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); | |
9a982250 | 2929 | |
cb8d68ec KS |
2930 | /* |
2931 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2932 | * This can happen if pages were freed under us. | |
2933 | */ | |
364c1eeb | 2934 | if (!split && list_empty(&ds_queue->split_queue)) |
cb8d68ec KS |
2935 | return SHRINK_STOP; |
2936 | return split; | |
9a982250 KS |
2937 | } |
2938 | ||
49071d43 | 2939 | #ifdef CONFIG_DEBUG_FS |
fa6c0231 | 2940 | static void split_huge_pages_all(void) |
49071d43 KS |
2941 | { |
2942 | struct zone *zone; | |
2943 | struct page *page; | |
630e7c5e | 2944 | struct folio *folio; |
49071d43 KS |
2945 | unsigned long pfn, max_zone_pfn; |
2946 | unsigned long total = 0, split = 0; | |
2947 | ||
fa6c0231 | 2948 | pr_debug("Split all THPs\n"); |
a17206da ML |
2949 | for_each_zone(zone) { |
2950 | if (!managed_zone(zone)) | |
2951 | continue; | |
49071d43 KS |
2952 | max_zone_pfn = zone_end_pfn(zone); |
2953 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
a17206da | 2954 | int nr_pages; |
49071d43 | 2955 | |
2b7aa91b | 2956 | page = pfn_to_online_page(pfn); |
630e7c5e KW |
2957 | if (!page || PageTail(page)) |
2958 | continue; | |
2959 | folio = page_folio(page); | |
2960 | if (!folio_try_get(folio)) | |
49071d43 KS |
2961 | continue; |
2962 | ||
630e7c5e | 2963 | if (unlikely(page_folio(page) != folio)) |
49071d43 KS |
2964 | goto next; |
2965 | ||
630e7c5e | 2966 | if (zone != folio_zone(folio)) |
49071d43 KS |
2967 | goto next; |
2968 | ||
630e7c5e KW |
2969 | if (!folio_test_large(folio) |
2970 | || folio_test_hugetlb(folio) | |
2971 | || !folio_test_lru(folio)) | |
49071d43 KS |
2972 | goto next; |
2973 | ||
2974 | total++; | |
630e7c5e KW |
2975 | folio_lock(folio); |
2976 | nr_pages = folio_nr_pages(folio); | |
2977 | if (!split_folio(folio)) | |
49071d43 | 2978 | split++; |
a17206da | 2979 | pfn += nr_pages - 1; |
630e7c5e | 2980 | folio_unlock(folio); |
49071d43 | 2981 | next: |
630e7c5e | 2982 | folio_put(folio); |
fa6c0231 | 2983 | cond_resched(); |
49071d43 KS |
2984 | } |
2985 | } | |
2986 | ||
fa6c0231 ZY |
2987 | pr_debug("%lu of %lu THP split\n", split, total); |
2988 | } | |
49071d43 | 2989 | |
fa6c0231 ZY |
2990 | static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) |
2991 | { | |
2992 | return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || | |
2993 | is_vm_hugetlb_page(vma); | |
2994 | } | |
2995 | ||
2996 | static int split_huge_pages_pid(int pid, unsigned long vaddr_start, | |
2997 | unsigned long vaddr_end) | |
2998 | { | |
2999 | int ret = 0; | |
3000 | struct task_struct *task; | |
3001 | struct mm_struct *mm; | |
3002 | unsigned long total = 0, split = 0; | |
3003 | unsigned long addr; | |
3004 | ||
3005 | vaddr_start &= PAGE_MASK; | |
3006 | vaddr_end &= PAGE_MASK; | |
3007 | ||
3008 | /* Find the task_struct from pid */ | |
3009 | rcu_read_lock(); | |
3010 | task = find_task_by_vpid(pid); | |
3011 | if (!task) { | |
3012 | rcu_read_unlock(); | |
3013 | ret = -ESRCH; | |
3014 | goto out; | |
3015 | } | |
3016 | get_task_struct(task); | |
3017 | rcu_read_unlock(); | |
3018 | ||
3019 | /* Find the mm_struct */ | |
3020 | mm = get_task_mm(task); | |
3021 | put_task_struct(task); | |
3022 | ||
3023 | if (!mm) { | |
3024 | ret = -EINVAL; | |
3025 | goto out; | |
3026 | } | |
3027 | ||
3028 | pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", | |
3029 | pid, vaddr_start, vaddr_end); | |
3030 | ||
3031 | mmap_read_lock(mm); | |
3032 | /* | |
3033 | * always increase addr by PAGE_SIZE, since we could have a PTE page | |
3034 | * table filled with PTE-mapped THPs, each of which is distinct. | |
3035 | */ | |
3036 | for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { | |
74ba2b38 | 3037 | struct vm_area_struct *vma = vma_lookup(mm, addr); |
fa6c0231 | 3038 | struct page *page; |
a644b0ab | 3039 | struct folio *folio; |
fa6c0231 | 3040 | |
74ba2b38 | 3041 | if (!vma) |
fa6c0231 ZY |
3042 | break; |
3043 | ||
3044 | /* skip special VMA and hugetlb VMA */ | |
3045 | if (vma_not_suitable_for_thp_split(vma)) { | |
3046 | addr = vma->vm_end; | |
3047 | continue; | |
3048 | } | |
3049 | ||
3050 | /* FOLL_DUMP to ignore special (like zero) pages */ | |
87d2762e | 3051 | page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); |
fa6c0231 | 3052 | |
f7091ed6 | 3053 | if (IS_ERR_OR_NULL(page)) |
fa6c0231 ZY |
3054 | continue; |
3055 | ||
a644b0ab MWO |
3056 | folio = page_folio(page); |
3057 | if (!is_transparent_hugepage(folio)) | |
fa6c0231 ZY |
3058 | goto next; |
3059 | ||
3060 | total++; | |
a644b0ab | 3061 | if (!can_split_folio(folio, NULL)) |
fa6c0231 ZY |
3062 | goto next; |
3063 | ||
a644b0ab | 3064 | if (!folio_trylock(folio)) |
fa6c0231 ZY |
3065 | goto next; |
3066 | ||
a644b0ab | 3067 | if (!split_folio(folio)) |
fa6c0231 ZY |
3068 | split++; |
3069 | ||
a644b0ab | 3070 | folio_unlock(folio); |
fa6c0231 | 3071 | next: |
a644b0ab | 3072 | folio_put(folio); |
fa6c0231 ZY |
3073 | cond_resched(); |
3074 | } | |
3075 | mmap_read_unlock(mm); | |
3076 | mmput(mm); | |
3077 | ||
3078 | pr_debug("%lu of %lu THP split\n", split, total); | |
3079 | ||
3080 | out: | |
3081 | return ret; | |
49071d43 | 3082 | } |
fa6c0231 | 3083 | |
fbe37501 ZY |
3084 | static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, |
3085 | pgoff_t off_end) | |
3086 | { | |
3087 | struct filename *file; | |
3088 | struct file *candidate; | |
3089 | struct address_space *mapping; | |
3090 | int ret = -EINVAL; | |
3091 | pgoff_t index; | |
3092 | int nr_pages = 1; | |
3093 | unsigned long total = 0, split = 0; | |
3094 | ||
3095 | file = getname_kernel(file_path); | |
3096 | if (IS_ERR(file)) | |
3097 | return ret; | |
3098 | ||
3099 | candidate = file_open_name(file, O_RDONLY, 0); | |
3100 | if (IS_ERR(candidate)) | |
3101 | goto out; | |
3102 | ||
3103 | pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", | |
3104 | file_path, off_start, off_end); | |
3105 | ||
3106 | mapping = candidate->f_mapping; | |
3107 | ||
3108 | for (index = off_start; index < off_end; index += nr_pages) { | |
1fb130b2 | 3109 | struct folio *folio = filemap_get_folio(mapping, index); |
fbe37501 ZY |
3110 | |
3111 | nr_pages = 1; | |
66dabbb6 | 3112 | if (IS_ERR(folio)) |
fbe37501 ZY |
3113 | continue; |
3114 | ||
9ee2c086 | 3115 | if (!folio_test_large(folio)) |
fbe37501 ZY |
3116 | goto next; |
3117 | ||
3118 | total++; | |
9ee2c086 | 3119 | nr_pages = folio_nr_pages(folio); |
fbe37501 | 3120 | |
9ee2c086 | 3121 | if (!folio_trylock(folio)) |
fbe37501 ZY |
3122 | goto next; |
3123 | ||
9ee2c086 | 3124 | if (!split_folio(folio)) |
fbe37501 ZY |
3125 | split++; |
3126 | ||
9ee2c086 | 3127 | folio_unlock(folio); |
fbe37501 | 3128 | next: |
9ee2c086 | 3129 | folio_put(folio); |
fbe37501 ZY |
3130 | cond_resched(); |
3131 | } | |
3132 | ||
3133 | filp_close(candidate, NULL); | |
3134 | ret = 0; | |
3135 | ||
3136 | pr_debug("%lu of %lu file-backed THP split\n", split, total); | |
3137 | out: | |
3138 | putname(file); | |
3139 | return ret; | |
3140 | } | |
3141 | ||
fa6c0231 ZY |
3142 | #define MAX_INPUT_BUF_SZ 255 |
3143 | ||
3144 | static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, | |
3145 | size_t count, loff_t *ppops) | |
3146 | { | |
3147 | static DEFINE_MUTEX(split_debug_mutex); | |
3148 | ssize_t ret; | |
fbe37501 ZY |
3149 | /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ |
3150 | char input_buf[MAX_INPUT_BUF_SZ]; | |
fa6c0231 ZY |
3151 | int pid; |
3152 | unsigned long vaddr_start, vaddr_end; | |
3153 | ||
3154 | ret = mutex_lock_interruptible(&split_debug_mutex); | |
3155 | if (ret) | |
3156 | return ret; | |
3157 | ||
3158 | ret = -EFAULT; | |
3159 | ||
3160 | memset(input_buf, 0, MAX_INPUT_BUF_SZ); | |
3161 | if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) | |
3162 | goto out; | |
3163 | ||
3164 | input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; | |
fbe37501 ZY |
3165 | |
3166 | if (input_buf[0] == '/') { | |
3167 | char *tok; | |
3168 | char *buf = input_buf; | |
3169 | char file_path[MAX_INPUT_BUF_SZ]; | |
3170 | pgoff_t off_start = 0, off_end = 0; | |
3171 | size_t input_len = strlen(input_buf); | |
3172 | ||
3173 | tok = strsep(&buf, ","); | |
3174 | if (tok) { | |
1212e00c | 3175 | strcpy(file_path, tok); |
fbe37501 ZY |
3176 | } else { |
3177 | ret = -EINVAL; | |
3178 | goto out; | |
3179 | } | |
3180 | ||
3181 | ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); | |
3182 | if (ret != 2) { | |
3183 | ret = -EINVAL; | |
3184 | goto out; | |
3185 | } | |
3186 | ret = split_huge_pages_in_file(file_path, off_start, off_end); | |
3187 | if (!ret) | |
3188 | ret = input_len; | |
3189 | ||
3190 | goto out; | |
3191 | } | |
3192 | ||
fa6c0231 ZY |
3193 | ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); |
3194 | if (ret == 1 && pid == 1) { | |
3195 | split_huge_pages_all(); | |
3196 | ret = strlen(input_buf); | |
3197 | goto out; | |
3198 | } else if (ret != 3) { | |
3199 | ret = -EINVAL; | |
3200 | goto out; | |
3201 | } | |
3202 | ||
3203 | ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); | |
3204 | if (!ret) | |
3205 | ret = strlen(input_buf); | |
3206 | out: | |
3207 | mutex_unlock(&split_debug_mutex); | |
3208 | return ret; | |
3209 | ||
3210 | } | |
3211 | ||
3212 | static const struct file_operations split_huge_pages_fops = { | |
3213 | .owner = THIS_MODULE, | |
3214 | .write = split_huge_pages_write, | |
3215 | .llseek = no_llseek, | |
3216 | }; | |
49071d43 KS |
3217 | |
3218 | static int __init split_huge_pages_debugfs(void) | |
3219 | { | |
d9f7979c GKH |
3220 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
3221 | &split_huge_pages_fops); | |
49071d43 KS |
3222 | return 0; |
3223 | } | |
3224 | late_initcall(split_huge_pages_debugfs); | |
3225 | #endif | |
616b8371 ZY |
3226 | |
3227 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
7f5abe60 | 3228 | int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, |
616b8371 ZY |
3229 | struct page *page) |
3230 | { | |
3231 | struct vm_area_struct *vma = pvmw->vma; | |
3232 | struct mm_struct *mm = vma->vm_mm; | |
3233 | unsigned long address = pvmw->address; | |
6c287605 | 3234 | bool anon_exclusive; |
616b8371 ZY |
3235 | pmd_t pmdval; |
3236 | swp_entry_t entry; | |
ab6e3d09 | 3237 | pmd_t pmdswp; |
616b8371 ZY |
3238 | |
3239 | if (!(pvmw->pmd && !pvmw->pte)) | |
7f5abe60 | 3240 | return 0; |
616b8371 | 3241 | |
616b8371 | 3242 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
8a8683ad | 3243 | pmdval = pmdp_invalidate(vma, address, pvmw->pmd); |
6c287605 | 3244 | |
088b8aa5 | 3245 | /* See page_try_share_anon_rmap(): invalidate PMD first. */ |
6c287605 DH |
3246 | anon_exclusive = PageAnon(page) && PageAnonExclusive(page); |
3247 | if (anon_exclusive && page_try_share_anon_rmap(page)) { | |
3248 | set_pmd_at(mm, address, pvmw->pmd, pmdval); | |
7f5abe60 | 3249 | return -EBUSY; |
6c287605 DH |
3250 | } |
3251 | ||
616b8371 ZY |
3252 | if (pmd_dirty(pmdval)) |
3253 | set_page_dirty(page); | |
4dd845b5 AP |
3254 | if (pmd_write(pmdval)) |
3255 | entry = make_writable_migration_entry(page_to_pfn(page)); | |
6c287605 DH |
3256 | else if (anon_exclusive) |
3257 | entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); | |
4dd845b5 AP |
3258 | else |
3259 | entry = make_readable_migration_entry(page_to_pfn(page)); | |
2e346877 PX |
3260 | if (pmd_young(pmdval)) |
3261 | entry = make_migration_entry_young(entry); | |
3262 | if (pmd_dirty(pmdval)) | |
3263 | entry = make_migration_entry_dirty(entry); | |
ab6e3d09 NH |
3264 | pmdswp = swp_entry_to_pmd(entry); |
3265 | if (pmd_soft_dirty(pmdval)) | |
3266 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
24bf08c4 DH |
3267 | if (pmd_uffd_wp(pmdval)) |
3268 | pmdswp = pmd_swp_mkuffd_wp(pmdswp); | |
ab6e3d09 | 3269 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); |
cea86fe2 | 3270 | page_remove_rmap(page, vma, true); |
616b8371 | 3271 | put_page(page); |
283fd6fe | 3272 | trace_set_migration_pmd(address, pmd_val(pmdswp)); |
7f5abe60 DH |
3273 | |
3274 | return 0; | |
616b8371 ZY |
3275 | } |
3276 | ||
3277 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
3278 | { | |
3279 | struct vm_area_struct *vma = pvmw->vma; | |
3280 | struct mm_struct *mm = vma->vm_mm; | |
3281 | unsigned long address = pvmw->address; | |
4fba8f2a | 3282 | unsigned long haddr = address & HPAGE_PMD_MASK; |
616b8371 ZY |
3283 | pmd_t pmde; |
3284 | swp_entry_t entry; | |
3285 | ||
3286 | if (!(pvmw->pmd && !pvmw->pte)) | |
3287 | return; | |
3288 | ||
3289 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
3290 | get_page(new); | |
2e346877 | 3291 | pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)); |
ab6e3d09 NH |
3292 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
3293 | pmde = pmd_mksoft_dirty(pmde); | |
3c811f78 | 3294 | if (is_writable_migration_entry(entry)) |
161e393c | 3295 | pmde = pmd_mkwrite(pmde, vma); |
8f34f1ea | 3296 | if (pmd_swp_uffd_wp(*pvmw->pmd)) |
f1eb1bac | 3297 | pmde = pmd_mkuffd_wp(pmde); |
2e346877 PX |
3298 | if (!is_migration_entry_young(entry)) |
3299 | pmde = pmd_mkold(pmde); | |
3300 | /* NOTE: this may contain setting soft-dirty on some archs */ | |
3301 | if (PageDirty(new) && is_migration_entry_dirty(entry)) | |
3302 | pmde = pmd_mkdirty(pmde); | |
616b8371 | 3303 | |
6c287605 DH |
3304 | if (PageAnon(new)) { |
3305 | rmap_t rmap_flags = RMAP_COMPOUND; | |
3306 | ||
3307 | if (!is_readable_migration_entry(entry)) | |
3308 | rmap_flags |= RMAP_EXCLUSIVE; | |
3309 | ||
4fba8f2a | 3310 | page_add_anon_rmap(new, vma, haddr, rmap_flags); |
6c287605 | 3311 | } else { |
cea86fe2 | 3312 | page_add_file_rmap(new, vma, true); |
6c287605 DH |
3313 | } |
3314 | VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new)); | |
4fba8f2a | 3315 | set_pmd_at(mm, haddr, pvmw->pmd, pmde); |
5cbcf225 MS |
3316 | |
3317 | /* No need to invalidate - it was non-present before */ | |
616b8371 | 3318 | update_mmu_cache_pmd(vma, address, pvmw->pmd); |
283fd6fe | 3319 | trace_remove_migration_pmd(address, pmd_val(pmde)); |
616b8371 ZY |
3320 | } |
3321 | #endif |